arXiv.orghttp://arxiv.org/icons/sfx.gifhttp://arxiv.org/
Constraints on the temperature inhomogeneity in quasar accretion discs from the ultraviolet-optical spectral variability. (arXiv:1503.00001v1 [astro-ph.GA])http://arxiv.org/abs/1503.00001
<p>The physical mechanisms of the quasar ultraviolet (UV)-optical variability
are not well understood despite the long history of observations. Recently,
Dexter &amp; Agol presented a model of quasar UV-optical variability, which assumes
large local temperature fluctuations in the quasar accretion discs. This
inhomogeneous accretion disc model is claimed to describe not only the
single-band variability amplitude, but also microlensing size constraints and
the quasar composite spectral shape. In this work, we examine the validity of
the inhomogeneous accretion disc model in the light of quasar UV-optical
spectral variability by using five-band multi-epoch light curves for nearly 9
000 quasars in the Sloan Digital Sky Survey (SDSS) Stripe 82 region. By
comparing the values of the intrinsic scatter $\sigma_{\text{int}}$ of the
two-band magnitude-magnitude plots for the SDSS quasar light curves and for the
simulated light curves, we show that Dexter &amp; Agol's inhomogeneous accretion
disc model cannot explain the tight inter-band correlation often observed in
the SDSS quasar light curves. This result leads us to conclude that the local
temperature fluctuations in the accretion discs are not the main driver of the
several years' UV-optical variability of quasars, and consequently, that the
assumption that the quasar accretion discs have large localized temperature
fluctuations is not preferred from the viewpoint of the UV-optical spectral
variability.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Kokubo_M/0/1/0/all/0/1">Mitsuru Kokubo</a> (Institute of Astronomy, School of Science, the University of Tokyo)A dusty, normal galaxy in the epoch of reionization. (arXiv:1503.00002v1 [astro-ph.GA])http://arxiv.org/abs/1503.00002
<p>Candidates for the modest galaxies that formed most of the stars in the early
universe, at redshifts $z &gt; 7$, have been found in large numbers with extremely
deep restframe-UV imaging. But it has proved difficult for existing
spectrographs to characterise them in the UV. The detailed properties of these
galaxies could be measured from dust and cool gas emission at far-infrared
wavelengths if the galaxies have become sufficiently enriched in dust and
metals. So far, however, the most distant UV-selected galaxy detected in dust
emission is only at $z = 3.25$, and recent results have cast doubt on whether
dust and molecules can be found in typical galaxies at this early epoch. Here
we report thermal dust emission from an archetypal early universe star-forming
galaxy, A1689-zD1. We detect its stellar continuum in spectroscopy and
determine its redshift to be $z = 7.5\pm0.2$ from a spectroscopic detection of
the Ly{\alpha} break. A1689-zD1 is representative of the star-forming
population during reionisation, with a total star-formation rate of about
12M$_\odot$ yr$^{-1}$. The galaxy is highly evolved: it has a large stellar
mass, and is heavily enriched in dust, with a dust-to-gas ratio close to that
of the Milky Way. Dusty, evolved galaxies are thus present among the fainter
star-forming population at $z &gt; 7$, in spite of the very short time since they
first appeared.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Watson_D/0/1/0/all/0/1">Darach Watson</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Christensen_L/0/1/0/all/0/1">Lise Christensen</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Knudsen_K/0/1/0/all/0/1">Kirsten Kraiberg Knudsen</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Richard_J/0/1/0/all/0/1">Johan Richard</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Gallazzi_A/0/1/0/all/0/1">Anna Gallazzi</a> (4,1), <a href="http://arxiv.org/find/astro-ph/1/au:+Michalowski_M/0/1/0/all/0/1">Micha&#x142; Jerzy Micha&#x142;owski</a> (5) ((1) DARK, U. Copenhagen, (2) Chalmers University, (3) CRAL, (4) INAF-Osservatorio di Arcetri, (5) IfA, Edinburgh)Evolution of the H$\beta$+[OIII] and [OII] luminosity functions and the [OII] star-formation history of the Universe up to $z$ ~ 5 from HiZELS. (arXiv:1503.00004v1 [astro-ph.GA])http://arxiv.org/abs/1503.00004
<p>We investigate the evolution of the H$\beta$+[OIII] and [OII] luminosity
functions from $z$ ~ 0.8 to ~ 5 in multiple redshift slices using data from the
High-$z$ Emission Line Survey (HiZELS). This is the first time that the
H$\beta$+[OIII] and [OII] luminosity functions have been studied at these
redshifts in a self-consistent analysis. This is also the largest sample of
[OII] and H$\beta$+[OIII] emitters (3484 and 3301 emitters, respectively) in
this redshift range, with large co-moving volumes ~ $1 \times 10^6$ Mpc$^{3}$
in two independent volumes (COSMOS and UDS), greatly reducing the effects of
cosmic variance. The emitters were selected by a combination of photometric
redshift and color-color selections, as well as spectroscopic follow-up,
including recent spectroscopic observations using DEIMOS and MOSFIRE on the
Keck Telescopes and FMOS on Subaru. We find a strong increase in $L_\star$ and
a decrease in $\phi_\star$ with increasing redshift up to $z \sim 2$ and $z
\sim 5$ for H$\beta$+[OIII] and [OII] emitters, respectively. For
H$\beta$+[OIII], this evolution then flattens by $z$ ~ 3. We derive the [OII]
star-formation history of the Universe since $z$ ~ 5 and find that the cosmic
SFRD rises from $z$ ~ 5 to ~ 3 and then drops towards $z$ ~ 0. We also find
that our star-formation history is able to reproduce the evolution of the
stellar mass density up to $z$ ~ 5. When comparing the H$\beta$+[OIII] SFRDs to
the [OII] and H$\alpha$ SFRD measurements in the literature, we find that there
is a remarkable agreement, suggesting that the H$\beta$+[OIII] sample is
dominated by star-forming galaxies at high-$z$ rather than AGNs.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Khostovan_A/0/1/0/all/0/1">Ali Ahmad Khostovan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sobral_D/0/1/0/all/0/1">David Sobral</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mobasher_B/0/1/0/all/0/1">Bahram Mobasher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Best_P/0/1/0/all/0/1">Philip N. Best</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smail_I/0/1/0/all/0/1">Ian Smail</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stott_J/0/1/0/all/0/1">John P. Stott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hemmati_S/0/1/0/all/0/1">Shoubaneh Hemmati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nayyeri_H/0/1/0/all/0/1">Hooshang Nayyeri</a>ATLASGAL - Kinematic distances and the dense gas mass distribution of the inner Galaxy. (arXiv:1503.00007v1 [astro-ph.SR])http://arxiv.org/abs/1503.00007
<p>The formation of high mass stars and clusters occurs in giant molecular
clouds. Objects in evolved stages of massive star formation such as protostars,
hot molecular cores, and ultracompact HII regions have been studied in more
detail than earlier, colder objects. With this in mind, the APEX Telescope
Large Area Survey of the whole inner Galactic plane at 870 micron (ATLASGAL)
has been carried out to provide a global view of cold dust and star formation
at submillimetre wavelengths. To derive kinematic distances to a large sample
of ATLASGAL clumps we divided them into groups of sources, which are located
close together, mostly within a radius of 2 pc, and have velocities in a
similar range with a median velocity dispersion of ~ 1 km/s. Using NH3, N2H+
and CS velocities we calculate near and far kinematic distances to 296 groups
of ATLASGAL sources in the first quadrant and 393 groups in the fourth
quadrant. We analyse HI self-absorption and HI absorption to resolve the
kinematic distance ambiguity. We obtain a scale height of ~ 28+/-2 pc and
displacement below the Galactic midplane of ~ -7+/-1 pc. Within distances from
2 to 18 kpc ATLASGAL clumps have a broad range of gas masses with a median of
1050 solar masses and a wide distribution of radii with a median of 0.4 pc.
Their distribution in galactocentric radii is correlated with spiral arms.
Using a statistically significant ATLASGAL sample we derive a power-law
exponent of -2.2+/-0.1 of the clump mass function. This is consistent with the
slope derived for clusters and with that of the stellar initial mass function.
Examining the power-law index for different galactocentric distances and
various source samples shows that it is independent of environment and
evolutionary phase. Fitting the mass-size relationship by a power law gives a
slope of 1.76+/-0.01 for cold sources such as IRDCs and warm clumps associated
with HII regions.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Wienen_M/0/1/0/all/0/1">M. Wienen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wyrowski_F/0/1/0/all/0/1">F. Wyrowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Menten_K/0/1/0/all/0/1">K. M. Menten</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Urquhart_J/0/1/0/all/0/1">J. S. Urquhart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Csengeri_T/0/1/0/all/0/1">T. Csengeri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walmsley_C/0/1/0/all/0/1">C. M. Walmsley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bontemps_S/0/1/0/all/0/1">S. Bontemps</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Russeil_D/0/1/0/all/0/1">D. Russeil</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bronfman_L/0/1/0/all/0/1">L. Bronfman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koribalski_B/0/1/0/all/0/1">B. S. Koribalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schuller_F/0/1/0/all/0/1">F. Schuller</a>Dark Matter Search Results from the PICO-2L C$_3$F$_8$ Bubble Chamber. (arXiv:1503.00008v1 [astro-ph.CO])http://arxiv.org/abs/1503.00008
<p>New data are reported from the operation of a 2-liter C$_3$F$_8$ bubble
chamber in the 2100 meter deep SNOLAB underground laboratory, with a total
exposure of 211.5 kg-days at four different recoil energy thresholds ranging
from 3.2 keV to 8.1 keV. These data show that C3F8 provides excellent electron
recoil and alpha rejection capabilities at very low thresholds, including the
first observation of a dependence of acoustic signal on alpha energy. Twelve
single nuclear recoil event candidates were observed during the run. The
candidate events exhibit timing characteristics that are not consistent with
the hypothesis of a uniform time distribution, and no evidence for a dark
matter signal is claimed. These data provide the most sensitive direct
detection constraints on WIMP-proton spin-dependent scattering to date, with
significant sensitivity at low WIMP masses for spin-independent WIMP-nucleon
scattering.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Amole_C/0/1/0/all/0/1">C. Amole</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ardid_M/0/1/0/all/0/1">M. Ardid</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Asner_D/0/1/0/all/0/1">D. M. Asner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baxter_D/0/1/0/all/0/1">D. Baxter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Behnke_E/0/1/0/all/0/1">E. Behnke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharjee_P/0/1/0/all/0/1">P. Bhattacharjee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borsodi_H/0/1/0/all/0/1">H. Borsodi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bou_Cabo_M/0/1/0/all/0/1">M. Bou-Cabo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brice_S/0/1/0/all/0/1">S. J. Brice</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Broemmelsiek_D/0/1/0/all/0/1">D. Broemmelsiek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_K/0/1/0/all/0/1">K. Clark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collar_J/0/1/0/all/0/1">J. I. Collar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cooper_P/0/1/0/all/0/1">P. S. Cooper</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crisler_M/0/1/0/all/0/1">M. Crisler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dahl_C/0/1/0/all/0/1">C. E. Dahl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Daley_S/0/1/0/all/0/1">S. Daley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Das_M/0/1/0/all/0/1">M. Das</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Debris_F/0/1/0/all/0/1">F. Debris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dhungana_N/0/1/0/all/0/1">N. Dhungana</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Farine_J/0/1/0/all/0/1">J. Farine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Felis_I/0/1/0/all/0/1">I. Felis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Filgas_R/0/1/0/all/0/1">R. Filgas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fines_Neuschild_M/0/1/0/all/0/1">M. Fines-Neuschild</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Girard_F/0/1/0/all/0/1">F. Girard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giroux_G/0/1/0/all/0/1">G. Giroux</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hai_M/0/1/0/all/0/1">M. Hai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hall_J/0/1/0/all/0/1">J. Hall</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harris_O/0/1/0/all/0/1">O. Harris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jackson_C/0/1/0/all/0/1">C. M. Jackson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jin_M/0/1/0/all/0/1">M. Jin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krauss_C/0/1/0/all/0/1">C. B. Krauss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lafreniere_M/0/1/0/all/0/1">M. Lafreni&#xe8;re</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Laurin_M/0/1/0/all/0/1">M. Laurin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lawson_I/0/1/0/all/0/1">I. Lawson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levine_I/0/1/0/all/0/1">I. Levine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lippincott_W/0/1/0/all/0/1">W. H. Lippincott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mann_E/0/1/0/all/0/1">E. Mann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martin_J/0/1/0/all/0/1">J. P. Martin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maurya_D/0/1/0/all/0/1">D. Maurya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mitra_P/0/1/0/all/0/1">P. Mitra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Neilson_R/0/1/0/all/0/1">R. Neilson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Noble_A/0/1/0/all/0/1">A. J. Noble</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Plante_A/0/1/0/all/0/1">A. Plante</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Podviianiuk_R/0/1/0/all/0/1">R. B. Podviianiuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Priya_S/0/1/0/all/0/1">S. Priya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Robinson_A/0/1/0/all/0/1">A. E. Robinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ruschman_M/0/1/0/all/0/1">M. Ruschman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scallon_O/0/1/0/all/0/1">O. Scallon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Seth_S/0/1/0/all/0/1">S. Seth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sonnenschein_A/0/1/0/all/0/1">A. Sonnenschein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starinski_N/0/1/0/all/0/1">N. Starinski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stekl_I/0/1/0/all/0/1">I. &#x160;tekl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vazquez_Jauregui_E/0/1/0/all/0/1">E. V&#xe0;zquez-Ja&#xf9;regui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wells_J/0/1/0/all/0/1">J. Wells</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wichoski_U/0/1/0/all/0/1">U. Wichoski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zacek_V/0/1/0/all/0/1">V. Zacek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_J/0/1/0/all/0/1">J. Zhang</a>The MLP Distribution: A Modified Lognormal Power-Law Model for the Stellar Initial Mass Function. (arXiv:1503.00023v1 [astro-ph.SR])http://arxiv.org/abs/1503.00023
<p>This work explores the mathematical properties of a distribution introduced
by Basu &amp; Jones (2004), and applies it to model the stellar initial mass
function (IMF). The distribution arises simply from an initial lognormal
distribution, requiring that each object in it subsequently undergoes
exponential growth but with an exponential distribution of growth lifetimes.
This leads to a modified lognormal with a power-law tail (MLP) distribution,
which can in fact be applied to a wide range of fields where distributions are
observed to have a lognormal-like body and a power-law tail. We derive
important properties of the MLP distribution, like the cumulative distribution,
the mean, variance, arbitrary raw moments, and a random number generator. These
analytic properties of the distribution can be used to facilitate application
to modeling the IMF. We demonstrate how the MLP function provides an excellent
fit to the IMF compiled by Chabrier (2005) and how this fit can be used to
quickly identify quantities like the mean, median, and mode, as well as number
and mass fractions in different mass intervals.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Basu_S/0/1/0/all/0/1">Shantanu Basu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gil_M/0/1/0/all/0/1">M. Gil</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Auddy_S/0/1/0/all/0/1">Sayantan Auddy</a>PAPER-64 Constraints On Reionization II: The Temperature Of The z=8.4 Intergalactic Medium. (arXiv:1503.00045v1 [astro-ph.CO])http://arxiv.org/abs/1503.00045
<p>We present constraints on both the kinetic temperature of the intergalactic
medium (IGM) at z=8.4, and on models for heating the IGM at high-redshift with
X-ray emission from the first collapsed objects. These constraints are derived
using a semi-analytic method to explore the new measurements of the 21 cm power
spectrum from the Donald C. Backer Precision Array for Probing the Epoch of
Reionization (PAPER), which were presented in a companion paper, Ali et al.
(2015). Twenty-one cm power spectra with amplitudes of hundreds of mK^2 can be
generically produced if the kinetic temperature of the IGM is significantly
below the temperature of the Cosmic Microwave Background (CMB); as such, the
new results from PAPER place lower limits on the IGM temperature at z=8.4.
Allowing for the unknown ionization state of the IGM, our measurements find the
IGM temperature to be above ~5 K for neutral fractions between 10% and 85%,
above ~7 K for neutral fractions between 15% and 80%, or above ~10 K for
neutral fractions between 30% and 70%. We also calculate the heating of the IGM
that would be provided by the observed high redshift galaxy population, and
find that for most models, these galaxies are sufficient to bring the IGM
temperature above our lower limits. However, there are significant ranges of
parameter space that could produce a signal ruled out by the PAPER
measurements; models with a steep drop-off in the star formation rate density
at high redshifts or with relatively low values for the X-ray to star formation
rate efficiency of high redshift galaxies are generally disfavored. The PAPER
measurements are consistent with (but do not constrain) a hydrogen spin
temperature above the CMB temperature, a situation which we find to be
generally predicted if galaxies fainter than the current detection limits of
optical/NIR surveys are included in calculations of X-ray heating.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Pober_J/0/1/0/all/0/1">Jonathan C. Pober</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ali_Z/0/1/0/all/0/1">Zaki S. Ali</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parsons_A/0/1/0/all/0/1">Aaron R. Parsons</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McQuinn_M/0/1/0/all/0/1">Matthew McQuinn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aguirre_J/0/1/0/all/0/1">James E. Aguirre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardi_G/0/1/0/all/0/1">Gianni Bernardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bradley_R/0/1/0/all/0/1">Richard F. Bradley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carilli_C/0/1/0/all/0/1">Chris L. Carilli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_C/0/1/0/all/0/1">Carina Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DeBoer_D/0/1/0/all/0/1">David R. DeBoer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dexter_M/0/1/0/all/0/1">Matthew R. Dexter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Furlanetto_S/0/1/0/all/0/1">Steven R. Furlanetto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grobbelaar_J/0/1/0/all/0/1">Jasper Grobbelaar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horrell_J/0/1/0/all/0/1">Jasper Horrell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jacobs_D/0/1/0/all/0/1">Daniel C. Jacobs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Klima_P/0/1/0/all/0/1">Patricia J. Klima</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kohn_S/0/1/0/all/0/1">Saul A. Kohn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_A/0/1/0/all/0/1">Adrian Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacMahon_D/0/1/0/all/0/1">David H. E. MacMahon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maree_M/0/1/0/all/0/1">Matthys Maree</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mesinger_A/0/1/0/all/0/1">Andrei Mesinger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moore_D/0/1/0/all/0/1">David F. Moore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Razavi_Ghods_N/0/1/0/all/0/1">Nima Razavi-Ghods</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stefan_I/0/1/0/all/0/1">Irina I. Stefan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walbrugh_W/0/1/0/all/0/1">William P. Walbrugh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walker_A/0/1/0/all/0/1">Andre Walker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_H/0/1/0/all/0/1">Haoxuan Zheng</a>Detailed Shape and Evolutionary Behavior of the X-ray Luminosity Function of Active Galactic Nuclei. (arXiv:1503.00056v1 [astro-ph.GA])http://arxiv.org/abs/1503.00056
<p>We construct the rest-frame 2--10 keV intrinsic X-ray luminosity function of
Active Galactic Nuclei (AGNs) from a combination of X-ray surveys from the
all-sky Swift BAT survey to the Chandra Deep Field-South. We use ~3200 AGNs in
our analysis, which covers six orders of magnitude in flux. The inclusion of
the XMM and Chandra COSMOS data has allowed us to investigate the detailed
behavior of the XLF and evolution. In deriving our XLF, we take into account
realistic AGN spectrum templates, absorption corrections, and probability
density distributions in photometric redshift. We present an analytical
expression for the overall behavior of the XLF in terms of the
luminosity-dependent density evolution, smoothed two power-law expressions in
11 redshift shells, three-segment power-law expression of the number density
evolution in four luminosity classes, and binned XLF. We observe a sudden
flattening of the low luminosity end slope of the XLF slope at z&gt;~0.6. Detailed
structures of the AGN downsizing have been also revealed, where the number
density curves have two clear breaks at all luminosity classes above log LX&gt;43.
The two break structure is suggestive of two-phase AGN evolution, consisting of
major merger triggering and secular processes.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Miyaji_T/0/1/0/all/0/1">T. Miyaji</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hasinger_G/0/1/0/all/0/1">G. Hasinger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salvato_M/0/1/0/all/0/1">M. Salvato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brusa_M/0/1/0/all/0/1">M. Brusa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cappelluti_N/0/1/0/all/0/1">N. Cappelluti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Civano_F/0/1/0/all/0/1">F. Civano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Puccetti_S/0/1/0/all/0/1">S. Puccetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elvis_M/0/1/0/all/0/1">M. Elvis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brunner_H/0/1/0/all/0/1">H. Brunner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fotopoulou_S/0/1/0/all/0/1">S. Fotopoulou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ueda_Y/0/1/0/all/0/1">Y. Ueda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Griffiths_R/0/1/0/all/0/1">R. E. Griffiths</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koekemoer_A/0/1/0/all/0/1">A. M. Koekemoer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Akiyama_M/0/1/0/all/0/1">M. Akiyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Comastri_A/0/1/0/all/0/1">A. Comastri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gilli_R/0/1/0/all/0/1">R. Gilli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lanzuisi_G/0/1/0/all/0/1">G. Lanzuisi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Merloni_A/0/1/0/all/0/1">A. Merloni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vignali_C/0/1/0/all/0/1">C. Vignali</a>Transiting Planets with LSST II. Period Detection of Planets Orbiting 1 Solar Mass Hosts. (arXiv:1503.00059v1 [astro-ph.EP])http://arxiv.org/abs/1503.00059
<p>The Large Synoptic Survey Telescope (LSST) will photometrically monitor ~1
billion stars for ten years. The resulting light curves can be used to detect
transiting exoplanets. In particular, as demonstrated by Lund et al. (2015),
LSST will probe stellar populations currently undersampled in most exoplanet
transit surveys, including out to extragalactic distances. In this paper we
test the efficiency of the box-fitting least-squares (BLS) algorithm for
accurately recovering the periods of transiting exoplanets using simulated LSST
data. We model planets with a range of radii orbiting a solar-mass star at a
distance of 7 kpc, with orbital periods ranging from 0.5 to 20 d. We find that
typical LSST observations will be able to reliably detect Hot Jupiters with
periods shorter than ~3 d. At the same time, we find that the LSST deep
drilling cadence is extremely powerful: the BLS algorithm successfully recovers
at least 30% of sub-Saturn-size exoplanets with orbital periods as long as 20
d.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Jacklin_S/0/1/0/all/0/1">Savannah R. Jacklin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lund_M/0/1/0/all/0/1">Michael B. Lund</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pepper_J/0/1/0/all/0/1">Joshua Pepper</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stassun_K/0/1/0/all/0/1">Keivan G. Stassun</a>Separating weak lensing and intrinsic alignments using radio observations. (arXiv:1503.00061v1 [astro-ph.CO])http://arxiv.org/abs/1503.00061
<p>We discuss methods for performing weak lensing using radio observations to
recover information about the intrinsic structural properties of the source
galaxies. Radio surveys provide unique information that can benefit weak
lensing studies, such as HI emission, which may be used to construct galaxy
velocity maps, and polarized synchrotron radiation; both of which provide
information about the unlensed galaxy and can be used to reduce galaxy shape
noise and the contribution of intrinsic alignments. Using a proxy for the
intrinsic position angle of an observed galaxy, we develop techniques for
cleanly separating weak gravitational lensing signals from intrinsic alignment
contamination in forthcoming radio surveys. Random errors on the intrinsic
orientation estimates introduce biases into the shear and intrinsic alignment
estimates. However, we show that these biases can be corrected for if the error
distribution is accurately known. We demonstrate our methods using simulations,
where we reconstruct the shear and intrinsic alignment auto and cross-power
spectra in three overlapping redshift bins. We find that the intrinsic position
angle information can be used to successfully reconstruct both the lensing and
intrinsic alignment power spectra with negligible residual bias.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Whittaker_L/0/1/0/all/0/1">Lee Whittaker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brown_M/0/1/0/all/0/1">Michael L. Brown</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Battye_R/0/1/0/all/0/1">Richard A. Battye</a>HATS-9b AND HATS-10b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION. (arXiv:1503.00062v1 [astro-ph.EP])http://arxiv.org/abs/1503.00062
<p>We report the discovery of two transiting extrasolar planets by the HATSouth
survey. HATS-9b orbits an old (10.8 $\pm$ 1.5 Gyr) V=13.3 G dwarf star, with a
period P = 1.9153 d. The host star has a mass of 1.03 M$_{\odot}$, radius of
1.503 R$_\odot$ and effective temperature 5366 $\pm$ 70 K. The planetary
companion has a mass of 0.837 M$_J$, and radius of 1.065 R$_J$ yielding a mean
density of 0.85 g cm$^{-3}$ . HATS-10b orbits a V=13.1 G dwarf star, with a
period P = 3.3128 d. The host star has a mass of 1.1 M$_\odot$, radius of 1.11
R$_\odot$ and effective temperature 5880 $\pm$ 120 K. The planetary companion
has a mass of 0.53 M$_J$, and radius of 0.97 R$_J$ yielding a mean density of
0.7 g cm$^{-3}$ . Both planets are compact in comparison with planets receiving
similar irradiation from their host stars, and lie in the nominal coordinates
of Field 7 of K2 but only HATS-9b falls on working silicon. Future
characterisation of HATS-9b with the exquisite photometric precision of the
Kepler telescope may provide measurements of its reflected light signature.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Brahm_R/0/1/0/all/0/1">R. Brahm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jordan_A/0/1/0/all/0/1">A. Jord&#xe1;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hartman_J/0/1/0/all/0/1">J.D. Hartman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bakos_G/0/1/0/all/0/1">G.&#xc1;. Bakos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bayliss_D/0/1/0/all/0/1">D. Bayliss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Penev_K/0/1/0/all/0/1">K. Penev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_G/0/1/0/all/0/1">G. Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ciceri_S/0/1/0/all/0/1">S. Ciceri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rabus_M/0/1/0/all/0/1">M. Rabus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Espinoza_N/0/1/0/all/0/1">N. Espinoza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mancini_L/0/1/0/all/0/1">L. Mancini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Val_Borro_M/0/1/0/all/0/1">M. de Val-Borro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhatti_W/0/1/0/all/0/1">W. Bhatti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sato_B/0/1/0/all/0/1">B. Sato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tan_T/0/1/0/all/0/1">T.G. Tan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Csubry_Z/0/1/0/all/0/1">Z. Csubry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Buchhave_L/0/1/0/all/0/1">L. Buchhave</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Henning_T/0/1/0/all/0/1">T. Henning</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmidt_B/0/1/0/all/0/1">B. Schmidt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suc_V/0/1/0/all/0/1">V. Suc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Noyes_R/0/1/0/all/0/1">R.W. Noyes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Papp_I/0/1/0/all/0/1">I. Papp</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazar_J/0/1/0/all/0/1">J. L&#xe1;z&#xe1;r</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sari_P/0/1/0/all/0/1">P. S&#xe1;ri</a>Cloud-cloud collision as a trigger of the high-mass star formation; a molecular line study in RCW120. (arXiv:1503.00070v1 [astro-ph.GA])http://arxiv.org/abs/1503.00070
<p>RCW120 is a Galactic HII region which has a beautiful infrared ring. Previous
studies on RCW120 provided a wealth of information on the second generation
star formation, but the origin of the exciting O star located inside the ring
structure has not been focused so far. Our new CO observations performed with
the NANTEN2, Mopra, and ASTE telescopes have revealed that two molecular clouds
with a velocity separation 20km/s are both physically associated with RCW120.
The cloud at -8km/s apparently traces the infrared ring, while the other cloud
at -28km/s is mainly distributed just outside the opening of the infrared ring,
interacting with the HII region as supported by high kinetic temperature of the
molecular gas and by the complementary distribution with the ionized gas. A
spherically expanding shell driven by the HII region is usually discussed as
the origin of the observed ring structure in RCW120. In this model, the neutral
material which surrounds the HII region is expected to have an expanding
motion. Our observations, however, indicate no evidence of the expanding motion
in the velocity space, being inconsistent with the expanding shell scenario. We
here postulate an alternative that, by applying the model introduced by Habe &amp;
Ohta (1992), the exciting O star in RCW120 was formed by a collision between
the present two clouds at a colliding velocity of ~30km/s. In the model, the
observed infrared ring can be interpreted as the cavity created in the larger
cloud by the collision, whose inner surface is illuminated by the strong UV
radiation after the birth of the O star. We argue that the present cloud-cloud
collision scenario explains the observed signatures of RCW120, i.e., its ring
morphology, coexistence of the two clouds and their large velocity separation,
and absence of the expanding motion.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Torii_K/0/1/0/all/0/1">K. Torii</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hasegawa_K/0/1/0/all/0/1">K. Hasegawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hattori_Y/0/1/0/all/0/1">Y. Hattori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sano_H/0/1/0/all/0/1">H. Sano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohama_A/0/1/0/all/0/1">A. Ohama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamamoto_H/0/1/0/all/0/1">H. Yamamoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tachihara_K/0/1/0/all/0/1">K. Tachihara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Soga_S/0/1/0/all/0/1">S. Soga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shimizu_S/0/1/0/all/0/1">S. Shimizu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Okuda_T/0/1/0/all/0/1">T. Okuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mizuno_N/0/1/0/all/0/1">N. Mizuno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Onishi_T/0/1/0/all/0/1">T. Onishi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mizuno_A/0/1/0/all/0/1">A. Mizuno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukui_Y/0/1/0/all/0/1">Y. Fukui</a>Abundance analysis of the recurrent nova RS Ophiuchi (2006 outburst). (arXiv:1503.00074v1 [astro-ph.SR])http://arxiv.org/abs/1503.00074
<p>We present an analysis of elemental abundances of ejecta of the recurrent
nova RS Oph using published optical and near-infrared spectra during the 2006
outburst. We use the CLOUDY photoionization code to generate synthetic spectra
by varying several parameters, the model generated spectra are then matched
with the observed emission line spectra obtained at two epochs. We obtain the
best fit model parameters through the $\chi^{2}$ minimization technique. Our
model results fit well with observed optical and near-infrared spectra. The
best-fit model parameters are compatible with a hot white dwarf source with
T$_{BB}$ of 5.5 - 5.8 $\times$ 10$^{5}$ K and roughly constant a luminosity of
6 - 8 $\times$ 10$^{36}$ ergs s$^{-1}$. From the analysis we find the following
abundances (by number) of elements with respect to solar: He/H = 1.8 $\pm$ 0.1,
N/H = 12.0 $\pm$ 1.0, O/H = 1.0 $\pm$ 0.4, Ne/H = 1.5 $\pm$ 0.1, Si/H = 0.4
$\pm$ 0.1, Fe/H = 3.2 $\pm$ 0.2, Ar/H = 5.1 $\pm$ 0.1, and Al/H = 1.0 $\pm$
0.1, all other elements were set at the solar abundance. This shows the ejecta
are significantly enhanced, relative to solar, in helium, nitrogen, neon, iron
and argon. Using the obtained parameter values, we estimate an ejected mass in
the range of 3.4 - 4.9 $\times$ 10$^{-6}$ M$_{\odot}$ which is consistent with
observational results.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Das_R/0/1/0/all/0/1">Ramkrishna Das</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mondal_A/0/1/0/all/0/1">Anindita Mondal</a>Observation of Chromospheric Sunspot at Millimeter Range with the Nobeyama 45 m Telescope. (arXiv:1503.00096v1 [astro-ph.SR])http://arxiv.org/abs/1503.00096
<p>The brightness temperature of the radio free-free emission at millimeter
range is an effective tool for characterizing the vertical structure of the
solar chromosphere. In this paper, we report on the first single-dish
observation of a sunspot at 85 and 115 GHz with sufficient spatial resolution
for resolving the sunspot umbra using the Nobeyama 45 m telescope. We used
radio attenuation material, i.e. a solar filter, to prevent the saturation of
the receivers. Considering the contamination from the plage by the side-lobes,
we found that the brightness temperature of the umbra should be lower than that
of the quiet region. This result is inconsistent with the preexisting
atmospheric models. We also found that the brightness temperature distribution
at millimeter range strongly corresponds to the ultraviolet (UV) continuum
emission at 1700 {\AA}, especially at the quiet region.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Iwai_K/0/1/0/all/0/1">Kazumasa Iwai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shimojo_M/0/1/0/all/0/1">Masumi Shimojo</a>Hojman Symmetry Approach for Scalar-Tensor Cosmology. (arXiv:1503.00098v1 [gr-qc])http://arxiv.org/abs/1503.00098
<p>Scalar-tensor Cosmologies can be dealt under the standard of the Hojman
conservation theorem that allows to fix the form of the coupling $F(\phi)$, of
the potential $V(\phi)$ and to find out exact solutions for related
cosmological models. Specifically, the existence of a symmetry transformation
vector for the equations of motion gives rise to a Hojman conserved quantity on
the corresponding minisuperpace and exact solutions for the cosmic scale factor
$a$ and the scalar field $\phi$ can be achieved. In particular, we take
advantage of the fact that minimally coupled solutions, previously obtained in
the Einstein frame, can be conformally transformed in non-minimally coupled
solutions in the Jordan frame. Some physically relevant examples are worked
out.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Paolella_M/0/1/0/all/0/1">Mariacristina Paolella</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Capozziello_S/0/1/0/all/0/1">Salvatore Capozziello</a>The multi-faceted synergy between Swift and Fermi in radio-loud AGN studies. (arXiv:1503.00099v1 [astro-ph.HE])http://arxiv.org/abs/1503.00099
<p>Since its launch in 2008 June, the Fermi Gamma-ray Space Telescope has opened
a new era in high-energy astrophysics. The unprecedented sensitivity, angular
resolution and effective area of the Large Area Telescope on board Fermi,
together with the nearly continuous observation of the entire gamma-ray sky
assures a formidable opportunity to study in detail gamma-ray emitting AGN of
various types. In this context the Swift satellite, thanks to its broad band
coverage and scheduling flexibility, creates a perfect synergy with Fermi.
</p>
<p>Swift and Fermi coordinated monitoring campaigns of radio-loud AGN allowed us
to investigate correlated variability at different frequencies and to build
time-resolved spectral energy distributions from optical to gamma-rays,
constraining the emission mechanisms at work in these objects. The rapid Swift
follow-up observations of gamma-ray flaring AGN detected by Fermi-LAT were also
fundamental in firmly associating the gamma-ray sources with their low-energy
counterparts. We present some interesting results obtained from Fermi-LAT and
Swift observations of gamma-ray flaring AGN in the first six years of Fermi
operation.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+DAmmando_F/0/1/0/all/0/1">F. D&#x27;Ammando</a> (INAF-IRA and DIFA-University of Bologna) <a href="http://arxiv.org/find/astro-ph/1/au:+Collaboration_on_behalf_of_the_Fermi_Large_Area_Telescope/0/1/0/all/0/1">on behalf of the Fermi Large Area Telescope Collaboration</a>Dark-energy dependent test of general relativity at cosmological scales. (arXiv:1503.00111v1 [astro-ph.CO])http://arxiv.org/abs/1503.00111
<p>The $\Lambda$CDM framework offers a remarkably good description of our
universe with a very small number of free parameters, which can be determined
with high accuracy from currently available data. However, this does not mean
that the associated physical quantities, such as the curvature of the universe,
have been directly measured. Similarly, general relativity is assumed, but not
tested. Testing the relevance of general relativity for cosmology at the
background level includes a verification of the relation between its energy
contents and the curvature of space. Using an extended Newtonian formulation,
we propose an approach where this relation can be tested. Using the recent
measurements on cosmic microwave background, baryonic acoustic oscillations and
the supernova Hubble diagram, we show that the prediction of general relativity
is well verified in the framework of standard $\Lambda$CDM assumptions, i.e. an
energy content only composed of matter and dark energy, in the form of a
cosmological constant or equivalently a vacuum contribution.
</p>
<p>However, the actual equation of state of dark fluids cannot be directly
obtained from cosmological observations. We found that relaxing the equation of
state of dark energy opens a large region of possibilities, revealing a new
type of degeneracy between the curvature and the total energy content of the
universe.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Zolnierowski_Y/0/1/0/all/0/1">Yves Zolnierowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blanchard_A/0/1/0/all/0/1">Alain Blanchard</a>Follow-up of X-ray transients detected by SWIFT with COLORES using the BOOTES network. (arXiv:1503.00123v1 [astro-ph.HE])http://arxiv.org/abs/1503.00123
<p>The Burst Observer and Optical Transient Exploring System (BOOTES) is a
network of telescopes that allows the continuous monitoring of transient
astrophysical sources. It was originally devoted to the study of the optical
emission from gamma-ray bursts (GRBs) that occur in the Universe. In this paper
we show the initial results obtained using the spectrograph COLORES (mounted on
BOOTES-2), when observing compact objects of diverse nature.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Caballero_Garcia_M/0/1/0/all/0/1">M. D. Caballero-Garcia</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Jelinek_M/0/1/0/all/0/1">M. Jelinek</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Castro_Tirado_A/0/1/0/all/0/1">A. J. Castro-Tirado</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Hudec_R/0/1/0/all/0/1">R. Hudec</a> (1,3), <a href="http://arxiv.org/find/astro-ph/1/au:+Cunniffe_R/0/1/0/all/0/1">R. Cunniffe</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Rabaza_O/0/1/0/all/0/1">O. Rabaza</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Sabau_Graziati_L/0/1/0/all/0/1">L. Sabau-Graziati</a> (5) ((1) CTU-FEL, Prague, (2) IAA-CSIC, (3) O. Ondrejov, (4) U. de Granada, (5) INTA-CSIC)Residual HCRF Rotation relative to the Inertial Coordinate System. (arXiv:1503.00136v1 [astro-ph.GA])http://arxiv.org/abs/1503.00136
<p>VLBI measurements of the absolute proper motions of 23 radio stars have been
collected from published data. These are stars with maser emission, or very
young stars, or asymptotic-giant-branch stars. By comparing these measurements
with the stellar proper motions from the optical catalogs of the Hipparcos
Celestial Reference Frame (HCRF), we have found the components of the residual
rotation vector of this frame relative to the inertial coordinate system:
(\omega_x,\omega_y,\omega_z) = (-0.39,-0.51,-1.25)+/-(0.58,0.57,0.56) mas/yr.
Based on all the available data, we have determined new values of the
components of the residual rotation vector for the optical realization of the
HCRF relative to the inertial coordinate system: (\omega_x,\omega_y,\omega_z) =
(-0.15,+0.24,-0.53)+/-(0.11,0.10,0.13) mas/yr.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Bobylev_V/0/1/0/all/0/1">V.V. Bobylev</a>Estimation of Apollo lunar dust transport using optical extinction measurements. (arXiv:1503.00154v1 [physics.geo-ph])http://arxiv.org/abs/1503.00154
<p>A technique to estimate mass erosion rate of surface soil during landing of
the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume
interaction is proposed and tested. The erosion rate is proportional to the
product of the second moment of the lofted particle size distribution N(D), and
third moment of the normalized soil size distribution S(D), divided by the
integral of S(D)D^2/v(D), where D is particle diameter and v(D) is the vertical
component of particle velocity. The second moment of N(D) is estimated by
optical extinction analysis of the Apollo cockpit video. Because of the
similarity between mass erosion rate of soil as measured by optical extinction
and rainfall rate as measured by radar reflectivity, traditional NWS
radar/rainfall correlation methodology can be applied to the lunar soil case
where various S(D) models are assumed corresponding to specific lunar sites.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Lane_J/0/1/0/all/0/1">John E. Lane</a>, <a href="http://arxiv.org/find/physics/1/au:+Metzger_P/0/1/0/all/0/1">Philip T. Metzger</a>Dipolar dynamos in stratified systems. (arXiv:1503.00165v1 [astro-ph.SR])http://arxiv.org/abs/1503.00165
<p>Observations of low-mass stars reveal a variety of magnetic field topologies
ranging from large-scale, axial dipoles to more complex magnetic fields. At the
same time, three-dimensional spherical simulations of convectively driven
dynamos reproduce a similar diversity, which is commonly obtained either with
Boussinesq models or with more realistic models based on the anelastic
approximation, which take into account the variation of the density with depth
throughout the convection zone. Nevertheless, a conclusion from different
anelastic studies is that dipolar solutions seem more difficult to obtain as
soon as substantial stratifications are considered. In this paper, we aim at
clarifying this point by investigating in more detail the influence of the
density stratification on dipolar dynamos. To that end, we rely on a systematic
parameter study that allows us to clearly follow the evolution of the stability
domain of the dipolar branch as the density stratification is increased. The
impact of the density stratification both on the dynamo onset and the dipole
collapse is discussed and compared to previous Boussinesq results. Furthermore,
our study indicates that the loss of the dipolar branch does not ensue from a
specific modification of the dynamo mechanisms related to the background
stratification, but could instead result from a bias as our observations
naturally favour a certain domain in the parameter space characterized by
moderate values of the Ekman number, owing to current computational
limitations. Moreover, we also show that the critical magnetic Reynolds number
of the dipolar branch is scarcely modified by the increase of the density
stratification, which provides an important insight into the global
understanding of the impact of the density stratification on the stability
domain of the dipolar dynamo branch.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Raynaud_R/0/1/0/all/0/1">R. Raynaud</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petitdemange_L/0/1/0/all/0/1">L. Petitdemange</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dormy_E/0/1/0/all/0/1">E. Dormy</a>Maximum entropy detection of planets around active stars. (arXiv:1503.00180v1 [astro-ph.EP])http://arxiv.org/abs/1503.00180
<p>(shortened for arXiv) We aim to progress towards more efficient exoplanet
detection around active stars by optimizing the use of Doppler Imaging in
radial velocity measurements. We propose a simple method to simultaneously
extract a brightness map and a set of orbital parameters through a tomographic
inversion technique derived from classical Doppler mapping. Based on the
maximum entropy principle, the underlying idea is to determine the set of
orbital parameters that minimizes the information content of the resulting
Doppler map. We carry out a set of numerical simulations to perform a
preliminary assessment of the robustness of our method, using an actual Doppler
map of the very active star HR 1099 to produce a realistic synthetic data set
for various sets of orbital parameters of a single planet in a circular orbit.
Using a simulated time-series of 50 line profiles affected by a peak-to-peak
activity jitter of 2.5 km/s, we are able in most cases to recover the radial
velocity amplitude, orbital phase and orbital period of an artificial planet
down to a radial velocity semi-amplitude of the order of the radial velocity
scatter due to the photon noise alone (about 50 m/s in our case). One
noticeable exception occurs when the planetary orbit is close to co-rotation,
in which case significant biases are observed in the reconstructed radial
velocity amplitude, while the orbital period and phase remain robustly
recovered. The present method constitutes a very simple way to extract orbital
parameters from heavily distorted line profiles of active stars, when more
classical radial velocity detection methods generally fail. It is easily
adaptable to most existing Doppler Imaging codes, paving the way towards a
systematic search for close-in planets orbiting young, rapidly-rotating stars.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Petit_P/0/1/0/all/0/1">P. Petit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Donati_J/0/1/0/all/0/1">J.-F. Donati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hebrard_E/0/1/0/all/0/1">E. H&#xe9;brard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morin_J/0/1/0/all/0/1">J. Morin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Folsom_C/0/1/0/all/0/1">C.P. Folsom</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bohm_T/0/1/0/all/0/1">T. B&#xf6;hm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boisse_I/0/1/0/all/0/1">I. Boisse</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borgniet_S/0/1/0/all/0/1">S. Borgniet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouvier_J/0/1/0/all/0/1">J. Bouvier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Delfosse_X/0/1/0/all/0/1">X. Delfosse</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hussain_G/0/1/0/all/0/1">G. Hussain</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jeffers_S/0/1/0/all/0/1">S.V. Jeffers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marsden_S/0/1/0/all/0/1">S.C. Marsden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barnes_J/0/1/0/all/0/1">J.R. Barnes</a>Short-period X-ray oscillations in super-soft novae and persistent SSS. (arXiv:1503.00186v1 [astro-ph.HE])http://arxiv.org/abs/1503.00186
<p>Transient short-period &lt;100s oscillations have been found in the X-ray light
curves of three novae during their SSS phase and in one persistent SSS. We
pursue an observational approach to determine possible driving mechanisms and
relations to fundamental system parameters such as the white dwarf mass.
</p>
<p>We performed a systematic search for short-period oscillations in all
available XMM-Newton and Chandra X-ray light curves of persistent SSS and novae
during their SSS phase. To study time evolution, we divided each light curve
into short time segments and computed power spectra. We then constructed
dynamic power spectra from which we identified transient periodic signals even
when only present for a short time. From all time segments of each system, we
computed fractions of time when periodic signals were detected.
</p>
<p>In addition to the previously known systems with short-period oscillations,
RS Oph (35s), KT Eri (35s), V339 Del (54s), and Cal 83 (67s), we found one
additional system, LMC 2009a (33s), and also confirm the 35s period from
Chandra data of KT Eri. The amplitudes of oscillations are of order &lt;15% of the
respective count rates and vary without any clear dependence on the X-ray count
rate. The fractions of the time when the respective periods were detected at
2-sigma significance (duty cycle) are 11.3%, 38.8%, 16.9%, 49.2%, and 18.7% for
LMC 2009a, RS Oph, KT Eri, V339 Del, and Cal 83, respectively. The respective
highest duty cycles found in a single observation are 38.1%, 74.5%, 61.4%,
67.8%, and 61.8%.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Ness_J/0/1/0/all/0/1">J.-U. Ness</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beardmore_A/0/1/0/all/0/1">A.P. Beardmore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Osborne_J/0/1/0/all/0/1">J.P. Osborne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuulkers_E/0/1/0/all/0/1">E. Kuulkers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Henze_M/0/1/0/all/0/1">M. Henze</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piro_A/0/1/0/all/0/1">A.L. Piro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Drake_J/0/1/0/all/0/1">J.J. Drake</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dobrotka_A/0/1/0/all/0/1">A. Dobrotka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schwarz_G/0/1/0/all/0/1">G. Schwarz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starrfield_S/0/1/0/all/0/1">S. Starrfield</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kretschmar_P/0/1/0/all/0/1">P. Kretschmar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirsch_M/0/1/0/all/0/1">M. Hirsch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilms_J/0/1/0/all/0/1">J. Wilms</a>Scaling properties of multitension domain wall networks. (arXiv:1503.00234v1 [hep-ph])http://arxiv.org/abs/1503.00234
<p>We study the asymptotic scaling properties of domain wall networks with three
different tensions in various cosmological epochs. We discuss the conditions
under which a scale-invariant evolution of the network (which is well
established for simpler walls) still applies, and also consider the limiting
case where defects are locally planar and the curvature is concentrated in the
junctions. We present detailed quantitative predictions for scaling densities
in various contexts, which should be testable by means of future
high-resolution numerical simulations.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Oliveira_M/0/1/0/all/0/1">M. F. Oliveira</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Martins_C/0/1/0/all/0/1">C. J. A. P. Martins</a>Rings and Radial Waves in the Disk of the Milky Way. (arXiv:1503.00257v1 [astro-ph.GA])http://arxiv.org/abs/1503.00257
<p>We show that in the anticenter region, between Galactic longitudes of
$110^\circ&lt;l&lt;229^\circ$, there is an oscillating asymmetry in the main sequence
star counts on either side of the Galactic plane using data from the Sloan
Digital Sky Survey. This asymmetry oscillates from more stars in the north at
distances of about 2 kpc from the Sun to more stars in the south at 4-6 kpc
from the Sun to more stars in the north at distances of 8-10 kpc from the Sun.
We also see evidence that there are more stars in the south at distances of
12-16 kpc from the Sun. The three more distant asymmetries form roughly
concentric rings around the Galactic center, opening in the direction of the
Milky Way's spiral arms. The northern ring, 9 kpc from the Sun, is easily
identified with the previously discovered Monoceros Ring. Parts of the southern
ring at 14 kpc from the Sun (which we call the TriAnd Ring) have previously
been identified as related to the Monoceros Ring and others have been called
the Triangulum Andromeda Overdensity. The two nearer oscillations are
approximated by a toy model in which the disk plane is offset by of the order
100 pc up and then down at different radii. We also show that the disk is not
azimuthally symmetric around the Galactic anticenter and that there could be a
correspondence between our observed oscillations and the spiral structure of
the Galaxy. Our observations suggest that the TriAnd and Monoceros Rings (which
extend to at least 25 kpc from the Galactic center) are primarily the result of
disk oscillations.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Xu_Y/0/1/0/all/0/1">Yan Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Newberg_H/0/1/0/all/0/1">Heidi Jo Newberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carlin_J/0/1/0/all/0/1">Jeffrey L. Carlin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_C/0/1/0/all/0/1">Chao Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deng_L/0/1/0/all/0/1">Licai Deng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_J/0/1/0/all/0/1">Jing Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schonrich_R/0/1/0/all/0/1">Ralph Sch&#xf6;nrich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yanny_B/0/1/0/all/0/1">Brian Yanny</a>Cusp Summations and Cusp Relations of Simple Quad Lenses. (arXiv:1503.00268v1 [astro-ph.CO])http://arxiv.org/abs/1503.00268
<p>We review five often used quad lens models, each of which has analytical
solutions and can produce four images at most. Each lens model has two
parameters, including one that describes the intensity of non-dimensional mass
density, and the other one that describes the deviation from the circular lens.
In our recent work, we have found that the cusp and the fold summations are not
equal to 0, when a point source infinitely approaches a cusp or a fold from
inner side of the caustic. Based on the magnification invariant theory, which
states that the sum of signed magnifications of the total images of a given
source is a constant, we calculate the cusp summations for the five lens
models. We find that the cusp summations are always larger than 0 for source on
the major cusps, while can be larger or smaller than 0 for source on the minor
cusps. We also find that if these lenses tend to the circular lens, the major
and minor cusp summations will have infinite values, and with positive and
negative signs respectively. The cusp summations do not change significantly if
the sources are slightly deviated from the cusps. In addition, through the
magnification invariants, we also derive the analytical signed cusp relations
on the axes for three lens models. We find that both on the major and the minor
axes the larger the lenses deviated from the circular lens, the larger the
signed cusp relations. The major cusp relations are usually larger than the
absolute minor cusp relations, but for some lens models with very large
deviation from circular lens, the minor cusp relations can be larger than the
major cusp relations.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Chu_Z/0/1/0/all/0/1">Zhe Chu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_G/0/1/0/all/0/1">G. L. Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_W/0/1/0/all/0/1">W. P. Lin</a>The resolved star-formation relation in nearby active galactic nuclei. (arXiv:1503.00280v1 [astro-ph.GA])http://arxiv.org/abs/1503.00280
<p>We present an analysis of the relation between star formation rate (SFR)
surface density (sigmasfr) and mass surface density of molecular gas
(sigmahtwo), commonly referred to as the Kennicutt-Schmidt (K-S) relation, at
its intrinsic spatial scale, i.e. the size of giant molecular clouds (10-150
pc), in the central, high-density regions of four nearby low-luminosity active
galactic nuclei (AGN). We used interferometric IRAM CO(1-0) and CO(2-1), and
SMA CO(3-2) emission line maps to derive sigmahtwo and HST-Halpha images to
estimate sigmasfr. Each galaxy is characterized by a distinct molecular SF
relation at spatial scales between 20 to 200 pc. The K-S relations can be
sub-linear, but also super-linear, with slopes ranging from 0.5 to 1.3.
Depletion times range from 1 and 2Gyr, compatible with results for nearby
normal galaxies. These findings are valid independently of which transition,
CO(1-0), CO(2-1), or CO(3-2), is used to derive sigmahtwo. Because of
star-formation feedback, life-time of clouds, turbulent cascade, or magnetic
fields, the K-S relation might be expected to degrade on small spatial scales
(&lt;100 pc). However, we find no clear evidence for this, even on scales as small
as 20 pc, and this might be because of the higher density of GMCs in galaxy
centers which have to resist higher shear forces. The proportionality between
sigmahtwo and sigmasfr found between 10 and 100 Msun/pc2 is valid even at high
densities, 10^3 Msun/pc2. However, by adopting a common CO-to-H2 conversion
factor (alpha_CO), the central regions of the galaxies have higher sigmasfr for
a given gas column than those expected from the models, with a behavior that
lies between the mergers/high-redshift starburst systems and the more quiescent
star-forming galaxies, assuming that the first ones require a lower value of
alpha_CO.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Casasola_V/0/1/0/all/0/1">Viviana Casasola</a> (1, 2), <a href="http://arxiv.org/find/astro-ph/1/au:+Hunt_L/0/1/0/all/0/1">Leslie Hunt</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Combes_F/0/1/0/all/0/1">Francoise Combes</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_Burillo_S/0/1/0/all/0/1">Santiago Garcia-Burillo</a> (4) ((1) INAF-IRA &amp; Italian ARC, (2) INAF-Arcetri, (3) Obs. de Paris LERMA, (4) Observatorio Astronomico Nacional (OAN)-Observatorio de Madrid)Comparing halo bias from abundance and clustering. (arXiv:1503.00313v1 [astro-ph.CO])http://arxiv.org/abs/1503.00313
<p>We model the abundance of haloes in the $\sim(3 \ \text{Gpc}/h)^3$ volume of
the MICE Grand Challenge simulation by fitting the universal mass function with
an improved Jack-Knife error covariance estimator that matches theory
predictions. We present unifying relations between different fitting models and
new predictions for linear ($b_1$) and non-linear ($c_2$ and $c_3$) halo
clustering bias. Different mass function fits show strong variations in their
overall poor performance when including the low mass range ($M_h \lesssim 3 \
10^{12} \ M_{\odot}/h$) in the analysis, which indicates noisy
friends-of-friends halo detection given the MICE resolution ($m_p \simeq 3 \
10^{10} \ M_{\odot}$/h). Together with fits from the literature we find an
overall variance in the amplitudes of around $10%$ in the low mass and up to
$50%$ in the high mass (galaxy cluster) range ($M_h &gt; 10^{14} \ M_{\odot}/h$).
These variations propagate into a $10%$ change in $b_1$ predictions and a $50%$
change in $c_2$ or $c_3$. Despite these strong variations we find tight
universal relations between $b_1$ and $c_2$ or $c_3$ for $b_1\gtrsim 1.5$ for
which we provide simple fits. Their dependence on the mass function fit
increases moderately for smaller $b_1$. Excluding low mass haloes, different
models fitted with reasonable goodness in this analysis, show percent level
agreement in their $b_1$ predictions, but are systematically $5-10%$ lower than
the bias directly measured with two-point halo-mass clustering. This result
confirms previous findings on larger volumes (and larger masses). Inaccuracies
in the bias predictions propagate into the prediction of bias ratios at two
redshifts, which would lead to $5-10%$ errors in growth measurements. They also
affect any HOD fitting or (cluster) mass calibration from clustering
measurements.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Hoffmann_K/0/1/0/all/0/1">Kai Hoffmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bel_J/0/1/0/all/0/1">Julien Bel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaztanaga_E/0/1/0/all/0/1">Enrique Gaztanaga</a>Uncertainties in polarimetric 3D reconstructions of coronal mass ejections. (arXiv:1503.00314v1 [astro-ph.SR])http://arxiv.org/abs/1503.00314
<p>This work is aimed at quantifying the uncertainties in the 3D reconstruction
of the location of coronal mass ejections (CMEs) obtained with the polarization
ratio technique. The method takes advantage of the different distributions
along the line of sight (LOS) of total (tB) and polarized (pB) brightnesses to
estimate the average location of the emitting plasma. To this end, we assumed
two simple electron density distributions along the LOS (a constant density and
Gaussian density profiles) for a plasma blob and synthesized the expected tB
and pB for different distances $z$ of the blob from the plane of the sky (POS)
and different projected altitudes $\rho$. Reconstructed locations of the blob
along the LOS were thus compared with the real ones, allowing a precise
determination of uncertainties in the method. Independently of the analytical
density profile, when the blob is centered at a small distance from the POS
(i.e. for limb CMEs) the distance from the POS starts to be significantly
overestimated. Polarization ratio technique provides the LOS position of the
center of mass of what we call folded density distribution, given by reflecting
and summing in front of the POS the fraction of density profile located behind
that plane. On the other hand, when the blob is far from the POS, but with very
small projected altitudes (i.e. for halo CMEs, $\rho &lt; 1.4$ R$_\odot$), the
inferred distance from that plane is significantly underestimated. Better
determination of the real blob position along the LOS is given for intermediate
locations, and in particular when the blob is centered at an angle of
$20^\circ$ from the POS. These result have important consequences not only for
future 3D reconstruction of CMEs with polarization ratio technique, but also
for the design of future coronagraphs aimed at providing a continuous
monitoring of halo-CMEs for space weather prediction purposes.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Bemporad_A/0/1/0/all/0/1">Alessandro Bemporad</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pagano_P/0/1/0/all/0/1">Paolo Pagano</a>Excitation properties of galaxies with the highest [OIII]/[OII] ratios: No evidence for massive escape of ionizing photons. (arXiv:1503.00320v1 [astro-ph.GA])http://arxiv.org/abs/1503.00320
<p>The possibility that star-forming galaxies may leak ionizing photons is at
the heart of many present-day studies that investigate the reionization of the
Universe. We test this hypothesis on local blue compact dwarf galaxies of very
high excitation. We assembled a sample of such galaxies by examining the
spectra from Data Releases 7 and 10 of the Sloan Digital Sky Survey. We argue
that reliable conclusions cannot be based on strong lines alone, and adopt a
strategy that includes important weak lines such as [OI] and the
high-excitation HeII and [ArIV] lines. Our analysis is based on purely
observational diagrams and on a comparison of photoionization models with
well-chosen emission-line ratio diagrams. We show that spectral energy
distributions from current stellar population synthesis models cannot account
for all the observational constraints, which led us to mimick several scenarios
that could explain the data. These include the additional presence of hard
X-rays or of shocks. We find that only ionization-bounded models (or models
with an escape fraction of ionizing photons lower than 10%) are able to
simultaneously explain all the observational constraints.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Stasinska_G/0/1/0/all/0/1">G. Stasinska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Izotov_Y/0/1/0/all/0/1">Yu. Izotov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morisset_C/0/1/0/all/0/1">C. Morisset</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guseva_N/0/1/0/all/0/1">N. Guseva</a>Correcting the record on the analysis of IBEX and STEREO data regarding variations in the neutral interstellar wind. (arXiv:1503.00341v1 [astro-ph.GA])http://arxiv.org/abs/1503.00341
<p>The journey of the Sun through space carries the solar system through a
dynamic interstellar environment that is presently characterized by Mach 1
motion between the heliosphere and the surrounding interstellar medium (ISM).
The interaction between the heliosphere and ISM is an evolving process due to
the variable solar wind and to interstellar turbulence. Frisch et al. presented
a meta-analysis of the historical data on the interstellar wind flowing through
the heliosphere and concluded that temporal changes in the ecliptic longitude
of the wind were statistically indicated by the data available in the refereed
literature at the time of that writing. Lallement and Bertaux disagree with
this result, and suggested, for instance, that a key instrumental response
function of IBEX-Lo was incorrect and that the STEREO pickup ion data are
unsuitable for diagnosing the flow of interstellar neutrals through the
heliosphere. Here we show that temporal variations in the interstellar wind
through the heliosphere are consistent with our knowledge of local ISM. The
statistical analysis of the historical helium wind data is revisited, and a
recent correction of a typographical error in the literature is incorporated
into the new fits. With this correction, and including no newer IBEX results,
these combined data still indicate that a change in the longitude of the
interstellar neutral wind over the past forty years is statistically likely,
but that a constant flow longitude is now also statistically possible. It is
shown that the IBEX instrumental response function is known, and that the
STEREO pickup ion data have been correctly utilized in this analysis.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Frisch_P/0/1/0/all/0/1">P. C. Frisch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bzowski_M/0/1/0/all/0/1">M. Bzowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Drews_C/0/1/0/all/0/1">C. Drews</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leonard_T/0/1/0/all/0/1">T. Leonard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Livadiotis_G/0/1/0/all/0/1">G. Livadiotis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McComas_D/0/1/0/all/0/1">D. J. McComas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moebius_E/0/1/0/all/0/1">E. Moebius</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schwadron_N/0/1/0/all/0/1">N. A. Schwadron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sokol_J/0/1/0/all/0/1">J. M. Sokol</a>Beyond Mixing-length Theory: a step toward 321D. (arXiv:1503.00342v1 [astro-ph.SR])http://arxiv.org/abs/1503.00342
<p>We present a physical basis for algorithms to replace mixing-length theory
(MLT) in stellar evolutionary computations. The 321D procedure is based on
three-dimensional (3D) time-dependent solutions of the Navier-Stokes equations,
including the Kolmogorov cascade as a sub-grid model of dissipation (implicit
large eddy simulations; ILES). We use Reynolds-averaged Navier-Stokes (RANS)
averaging to make 3D simulation data concise, and use 3D simulations to give
RANS closure. We sketch a simple algorithm, which is non-local and
time-dependent, with both MLT and the Lorenz convective roll as particular
subsets of solutions. The damping length is determined from a balance between
the large-scale driving and damping at the Kolmogorov scale.
</p>
<p>We find that (1) braking regions (boundary layers in which mixing occurs)
automatically appear {\it beyond} the edges of convection as defined by the
Schwarzschild criterion, (2) dynamic (non-local) terms imply a non-zero
turbulent kinetic energy flux (unlike MLT), (3) the effects of composition
gradients on flow are important, and (4) convective boundaries in
neutrino-cooled stages differ in nature from those in photon-cooled stages. The
321D approach may be easily generalized, and allows connections with modern
research on turbulent flow of solar and terrestrial fluids and plasmas.
Calibration to astronomical systems is unnecessary, so the approach can be
predictive rather than merely descriptive. Implications for solar abundances,
helioseismology, asteroseismology, nucleosynthesis yields, supernova
progenitors and core collapse are indicated.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Arnett_W/0/1/0/all/0/1">W. David Arnett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meakin_C/0/1/0/all/0/1">Casey Meakin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Viallet_M/0/1/0/all/0/1">Maxime Viallet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Campbell_S/0/1/0/all/0/1">Simon W. Campbell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lattanzio_J/0/1/0/all/0/1">John Lattanzio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mocak_M/0/1/0/all/0/1">Miroslav Mo&#x107;ak</a>On the detection of point sources in Planck LFI 70 GHz CMB maps based on cleaned K-map. (arXiv:1503.00346v1 [astro-ph.GA])http://arxiv.org/abs/1503.00346
<p>We use the Planck LFI 70GHz data to further probe point source detection
technique in the sky maps of the cosmic microwave background (CMB) radiation.
The method developed by Tegmark et al. for foreground reduced maps and the
Kolmogorov parameter as the descriptor are adopted for the analysis of Planck
satellite CMB temperature data. Most of the detected points coincide with point
sources already revealed by other methods. However, we have also found 9 source
candidates for which still no counterparts are known.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Khachatryan_H/0/1/0/all/0/1">H.G. Khachatryan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kashin_A/0/1/0/all/0/1">A.L. Kashin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poghosyan_E/0/1/0/all/0/1">E. Poghosyan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yegoryan_G/0/1/0/all/0/1">G. Yegoryan</a>A New Merging Double Degenerate Binary in the Solar Neighborhood. (arXiv:1503.00349v1 [astro-ph.SR])http://arxiv.org/abs/1503.00349
<p>Characterizing the local space density of double degenerate binary systems is
a complementary approach to broad sky surveys of double degenerates to
determine the expected rates of white dwarf binary mergers, in particular those
that may evolve into other observable phenomena such as extreme helium stars,
Am CVn systems, and supernovae Ia. However, there have been few such systems
detected in local space. We report here the discovery that WD 1242$-$105, a
nearby bright WD, is a double-line spectroscopic binary consisting of two
degenerate DA white dwarfs of similar mass and temperature, despite it
previously having been spectroscopically characterized as a single degenerate.
Follow-up photometry, spectroscopy, and trigonometric parallax have been
obtained in an effort to determine the fundamental parameters of each component
of this system. The binary has a mass ratio of 0.7 and a trigonometric parallax
of 25.5 mas, placing it at a distance of 39 pc. The system's total mass is 0.95
M$_\odot$ and has an orbital period of 2.85 hours, making it the strongest
known gravitational wave source ($\log h = -20.78$) in the mHz regime. Because
of its orbital period and total mass, WD 1242$-$105 is predicted to merge via
gravitational radiation on a timescale of 740 Myr, which will most likely not
result in a catastrophic explosion.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Debes_J/0/1/0/all/0/1">John H. Debes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kilic_M/0/1/0/all/0/1">Mukremin Kilic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tremblay_P/0/1/0/all/0/1">Pier-Emmanuel Tremblay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_Morales_M/0/1/0/all/0/1">Mercedes L&#xf3;pez-Morales</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anglada_Escude_G/0/1/0/all/0/1">Guillem Anglada-Escud&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Napiwotzki_R/0/1/0/all/0/1">Ralf Napiwotzki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Osip_D/0/1/0/all/0/1">David Osip</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weinberger_A/0/1/0/all/0/1">Alycia Weinberger</a>Evidence for an interstellar dust filament in the outer heliosheath. (arXiv:1503.00353v1 [astro-ph.GA])http://arxiv.org/abs/1503.00353
<p>A recently discovered filament of polarized starlight that traces a coherent
magnetic field is shown to have several properties that are consistent with an
origin in the outer heliosheath of the heliosphere: (1) The magnetic field that
provides the best fit to the polarization position angles is directed within
6.7+-11 degrees of the observed upwind direction of the flow of interstellar
neutral helium gas through the heliosphere. (2) The magnetic field is ordered;
the component of the variation of the polarization position angles that can be
attributed to magnetic turbulence is small. (3) The axis of the elongated
filament can be approximated by a line that defines an angle of 80+/-14 degrees
with the plane that is formed by the interstellar magnetic field vector and the
vector of the inflowing neutral gas (the "BV" plane). We propose that this
polarization feature arises from aligned interstellar dust grains in the outer
heliosheath where the interstellar plasma and magnetic field are deflected
around the heliosphere. The proposed outer heliosheath location of the
polarizing grains requires confirmation by modeling grain-propagation through
three-dimensional MHD heliosphere models that simultaneously calculate torques
on asymmetric dust grains interacting with the heliosphere.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Frisch_P/0/1/0/all/0/1">P. C. Frisch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andersson_B/0/1/0/all/0/1">B-G Andersson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berdyugin_A/0/1/0/all/0/1">A. Berdyugin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Funsten_H/0/1/0/all/0/1">H. O. Funsten</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Magalhaes_A/0/1/0/all/0/1">A. M. Magalhaes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McComas_D/0/1/0/all/0/1">D. J. McComas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piirola_V/0/1/0/all/0/1">V. Piirola</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schwadron_N/0/1/0/all/0/1">N. A. Schwadron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Seriacopi_D/0/1/0/all/0/1">D. B. Seriacopi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Slavin_J/0/1/0/all/0/1">J. D. Slavin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wiktorowicz_S/0/1/0/all/0/1">S. J. Wiktorowicz</a>Search for an emission line of a gravitational wave background. (arXiv:1503.00354v1 [gr-qc])http://arxiv.org/abs/1503.00354
<p>In the light of the history of researches on electromagnetic wave spectrum, a
sharp emission line of gravitational-wave background (GWB) would be an
interesting observational target. Here we study an efficient method to detect a
line GWB by correlating data of multiple ground-based detectors. We find that
the width of frequency bin for coarse graining is a critical parameter, and the
commonly-used value 0.25 Hz is far from optimal, decreasing the signal-to-noise
ratio by up to a factor of seven. By reanalyzing the existing data with a
smaller bin width, we might detect a precious line signal from the early
universe.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Nishizawa_A/0/1/0/all/0/1">Atsushi Nishizawa</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Seto_N/0/1/0/all/0/1">Naoki Seto</a>Observations of Binary Stars with the Differential Speckle Survey Instrument. V. Toward an Empirical Metal-Poor Mass-Luminosity Relation. (arXiv:1503.00363v1 [astro-ph.SR])http://arxiv.org/abs/1503.00363
<p>In an effort to better understand the details of the stellar structure and
evolution of metal poor stars, the Gemini North telescope was used on two
occasions to take speckle imaging data of a sample of known spectroscopic
binary stars and other nearby stars in order to search for and resolve close
companions. The observations were obtained using the Differential Speckle
Survey Instrument, which takes data in two filters simultaneously. The results
presented here are of 90 observations of 23 systems in which one or more
companions was detected, and 6 stars where no companion was detected to the
limit of the camera capabilities at Gemini. In the case of the binary and
multiple stars, these results are then further analyzed to make first orbit
determinations in five cases, and orbit refinements in four other cases. Mass
information is derived, and since the systems span a range in metallicity, a
study is presented that compares our results with the expected trend in total
mass as derived from the most recent Yale isochrones as a function of metal
abundance. These data suggest that metal-poor main-sequence stars are less
massive at a given color than their solar-metallicity analogues in a manner
consistent with that predicted from the theory.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Horch_E/0/1/0/all/0/1">Elliott P. Horch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altena_W/0/1/0/all/0/1">William F. van Altena</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Demarque_P/0/1/0/all/0/1">Pierre Demarque</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Howell_S/0/1/0/all/0/1">Steve B. Howell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Everett_M/0/1/0/all/0/1">Mark E. Everett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ciardi_D/0/1/0/all/0/1">David R. Ciardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teske_J/0/1/0/all/0/1">Johanna K. Teske</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Henry_T/0/1/0/all/0/1">Todd J. Henry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Winters_J/0/1/0/all/0/1">Jennifer G. Winters</a>Neutron-proton effective mass splitting in neutron-rich matter and its impacts on nuclear reactions. (arXiv:1503.00370v1 [nucl-th])http://arxiv.org/abs/1503.00370
<p>The neutron-proton effective mass splitting in neutron-rich nucleonic matter
reflects the space-time nonlocality of the isovector nuclear interaction. It
affects the neutron/proton ratio during the earlier evolution of the Universe,
cooling of protoneutron stars, structure of rare isotopes and dynamics of
heavy-ion collisions. While there is still no consensus on whether the
neutron-proton effective mass splitting is negative, zero or positive and how
it depends on the density as well as the isospin-asymmetry of the medium,
significant progress has been made in recent yeas in addressing these issues.
We first recall the connections among the neutron-proton effective mass
splitting, the momentum dependence of the isovector potential and the density
dependence of the symmetry energy. We then make a few observations about the
progress in calculating the neutron-proton effective mass splitting using
various nuclear many-body theories and its effects on the isospin-dependence of
in-medium nucleon-nucleon cross sections. Perhaps, our most reliable knowledge
so far about the neutron-proton effective mass splitting at saturation density
of nuclear matter comes from optical model analyses of huge sets of
nucleon-nucleus scattering data accumulated over the last five decades. The
momentum dependence of the symmetry potential from these analyses provide a
useful boundary condition at saturation density for calibrating nuclear
many-body calculations. Several observables in heavy-ion collisions have been
identified as sensitive probes of the neutron-proton effective mass splitting
in dense neutron-rich matter based on transport model simulations. We review
these observables and comment on the latest experimental findings.
</p>
<a href="http://arxiv.org/find/nucl-th/1/au:+Li_B/0/1/0/all/0/1">Bao-An Li</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Chen_L/0/1/0/all/0/1">Lie-Wen Chen</a>Disappearance of Comet C/2010 X1 (Elenin): Gone with a Whimper, not a Bang. (arXiv:1503.00387v1 [astro-ph.EP])http://arxiv.org/abs/1503.00387
<p>We examine the rise and sudden demise of comet C/2010 X1 (Elenin) on its
approach to perihelion. Discovered inbound at 4.2 AU, this long-period comet
was predicted to become very bright when near perihelion, at 0.48 AU on 2011
September 10. Observations starting 2011 February (heliocentric distance
$\sim$3.5 AU) indeed show the comet to brighten by about 11 magnitudes, with
most of the increase occurring inside 1 AU from the Sun. The peak brightness
reached $m_R$ = 6 on UT 2011 August 12.95$\pm$0.50, when at $\sim$0.83 AU from
the Sun. We find that most of the surge in brightness in mid-August resulted
from dust particle forward-scattering, not from a sudden increase in the
activity. A much smaller ($\sim$3 magnitudes) brightening reached a maximum on
UT 2011 August 30$\pm$1 (at 0.56 AU), and reflects the true break-up of the
nucleus. This second peak was matched by a change in the morphology from
centrally condensed to diffuse. The estimated cross-section of the nucleus when
at 1 AU inbound was $\sim$1 km$^2$, corresponding to an equal-area circle of
radius 0.6 km. No surviving fragments were found to a limiting red magnitude
$r'$ = 24.4, corresponding to radii $\lesssim$40 m (red geometric albedo = 0.04
assumed). Our observations are consistent with disintegration of the nucleus
into a power law size distribution of fragments with index $q$ = 3.3$\pm$0.2
combined with the action of radiation pressure. We speculate about physical
processes that might cause nucleus disruption in a comet when still 0.7 AU from
the Sun. Tidal stresses and devolatilization of the nucleus by sublimation are
both negligible at this distance. However, the torque caused by mass loss, even
at the very low rates measured in comet Elenin, is potentially large enough to
be responsible by driving the nucleus to rotational instability.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Li_J/0/1/0/all/0/1">Jing Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jewitt_D/0/1/0/all/0/1">David Jewitt</a>Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation. (arXiv:1503.00394v1 [astro-ph.GA])http://arxiv.org/abs/1503.00394
<p>The HDO/H2O ratio in interstellar gas is often used to draw conclusions on
the origin of water in star-forming regions and on Earth. In cold cores and in
the outer regions of protoplanetary disks, gas-phase water comes from
photodesorption of water ice. We present fitting formulae for implementation in
astrochemical models using photodesorption efficiencies for all water ice
isotopologues obtained using classical molecular dynamics simulations. We
investigate if the gas-phase HDO/H2O ratio reflects that present in the ice or
whether fractionation can occur during photodesorption. Probabilities for the
top four monolayers are presented for photodesorption of X (X=H,D) atoms, OX
radicals, and X2O and HDO molecules following photodissociation of H2O, D2O,
and HDO in H2O amorphous ice at temperatures from 10-100 K. Isotope effects are
found for all products: (1) H atom photodesorption probabilities from H2O ice
are larger than those for D atom photodesorption from D2O ice by a factor of
1.1; the ratio of H and D photodesorbed upon HDO photodissociation is a factor
of 2. This process will enrich the ice in deuterium atoms over time; (2) the
OD/OH photodesorption ratio upon D2O and H2O photodissociation is on average a
factor of 2, but the ratio upon HDO photodissociation is almost constant at
unity for all temperatures; (3) D atoms are more effective in kicking out
neighbouring water molecules than H atoms. However, the ratio of the
photodesorbed HDO and H2O molecules is equal to the HDO/H2O ratio in the ice,
therefore, there is no isotope fractionation upon HDO and H2O photodesorption.
Nevertheless, the enrichment of the ice in D atoms due to photodesorption can
over time lead to an enhanced HDO/H2O ratio in the ice, and, when
photodesorbed, also in the gas. The extent to which the ortho/para ratio of H2O
can be modified by the photodesorption process is also discussed. (Abridged)
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Arasa_C/0/1/0/all/0/1">Carina Arasa</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Koning_J/0/1/0/all/0/1">Jesper Koning</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Kroes_G/0/1/0/all/0/1">Geert-Jan Kroes</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Walsh_C/0/1/0/all/0/1">Catherine Walsh</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Dishoeck_E/0/1/0/all/0/1">Ewine F. van Dishoeck</a> (2,3) ((1) Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P. O. Box 9502, 2300 RA Leiden, The Netherlands, (2) Leiden Observatory, Leiden University, P. O. Box 9513, 2300 RA Leiden, The Netherlands, (3) Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748 Garching, Germany)The Evolution of Interacting Spiral Galaxy NGC 5194. (arXiv:1503.00398v1 [astro-ph.GA])http://arxiv.org/abs/1503.00398
<p>NGC 5194 (M51a) is a grand-design spiral galaxy and undergoing interactions
with its companion. Here we focus on investigating main properties of its
star-formation history (SFH) by constructing a simple evolution model, which
assumes that the disc builds up gradually by cold gas infall and the gas infall
rate can be parameterizedly described by a Gaussian form. By comparing model
predictions with the observed data, we discuss the probable range for free
parameter in the model and then know more about the main properties of the
evolution and SFH of M51a. We find that the model predictions are very
sensitive to the free parameter and the model adopting a constant infall-peak
time $t_{\rm p}\,=\,7.0{\rm Gyr}$ can reproduce most of the observed
constraints of M51a. Although our model does not assume the gas infall
time-scale of the inner disc is shorter than that of the outer disc, our model
predictions still show that the disc of M51a forms inside-out. We find that the
mean stellar age of M51a is younger than that of the Milky Way, but older than
that of the gas-rich disc galaxy UGC 8802. In this paper, we also introduce a
'toy' model to allow an additional cold gas infall occurred recently to imitate
the influence of the interaction between M51a and its companion. Our results
show that the current molecular gas surface density, the SFR and the UV-band
surface brightness are important quantities to trace the effects of recent
interaction on galactic SF process.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Kang_X/0/1/0/all/0/1">Xiaoyu Kang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chang_R/0/1/0/all/0/1">Ruixiang Chang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_F/0/1/0/all/0/1">Fenghui Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_L/0/1/0/all/0/1">Liantao Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_L/0/1/0/all/0/1">Lang Wang</a>DAMPE silicon tracker on-board data compression algorithm. (arXiv:1503.00415v1 [astro-ph.IM])http://arxiv.org/abs/1503.00415
<p>The Dark Matter Particle Explorer (DAMPE) is an upcoming scientific satellite
mission for high energy gamma-ray, electron and cosmic rays detection. The
silicon tracker (STK) is a sub detector of the DAMPE payload with an excellent
position resolution (readout pitch of 242um), which measures the incident
direction of particles, as well as charge. The STK consists 12 layers of
Silicon Micro-strip Detector (SMD), equivalent to a total silicon area of
6.5m$^2$. The total readout channels of the STK are 73728, which leads to a
huge amount of raw data to be dealt. In this paper, we focus on the on-board
data compression algorithm and procedure in the STK, which was initially
verified by cosmic-ray measurements.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Dong_Y/0/1/0/all/0/1">Yifan Dong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_F/0/1/0/all/0/1">Fei Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qiao_R/0/1/0/all/0/1">Rui Qiao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peng_W/0/1/0/all/0/1">Wenxi Peng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fan_R/0/1/0/all/0/1">Ruirui Fan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gong_K/0/1/0/all/0/1">Ke Gong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_D/0/1/0/all/0/1">Di Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_H/0/1/0/all/0/1">Huanyu Wang</a>Alignments Of Black Holes With Their Warped Accretion Disks And Episodic Lifetimes Of Active Galactic Nuclei. (arXiv:1503.00432v1 [astro-ph.GA])http://arxiv.org/abs/1503.00432
<p>Warped accretion disks have attracted intensive attention because of their
critical role on shaping the spin of supermassive massive black holes (SMBHs)
through the Bardeen-Petterson effect, a general relativistic effect that leads
to final alignments or anti-alignments between black holes and warped accretion
disks. We study such alignment processes by explicitly taking into account the
finite sizes of accretion disks and the episodic lifetimes of AGNs that
delineate the duration of gas fueling onto accretion disks. We employ an
approximate global model to simulate the evolution of accretion disks, allowing
to determine the gravitomagnetic torque that drives the alignments in a quite
simple way. We then track down the evolutionary paths for mass and spin of
black holes both in a single activity episode and over a series of episodes.
Given with randomly and isotropically oriented gas fueling over episodes, we
calculate the spin evolution with different episodic lifetimes and find that it
is quite sensitive to the lifetimes. We therefore propose that spin
distribution of SMBHs can place constraints on the episodic lifetimes of AGNs
and vice versa. Applications of our results on the observed spin distributions
of SMBHs and the observed episodic lifetimes of AGNs are discussed, although
both the measurements at present are yet ambiguous to draw a firm conclusion.
Our prescription can be easily incorporated into semi-analytic models for black
hole growth and spin evolution.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Li_Y/0/1/0/all/0/1">Yan-Rong Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Jian-Min Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_C/0/1/0/all/0/1">Cheng Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qiu_J/0/1/0/all/0/1">Jie Qiu</a>High-Energy Neutrinos in Light of Fermi-LAT. (arXiv:1503.00437v1 [astro-ph.HE])http://arxiv.org/abs/1503.00437
<p>The production of high-energy astrophysical neutrinos is tightly linked to
the emission of hadronic gamma-rays. I will discuss the recent observation of
TeV to PeV neutrinos by the IceCube Cherenkov telescope in the context of
gamma-ray astronomy. The corresponding energy range of hadronic gamma-rays is
not directly accessible by extragalactic gamma-ray astronomy due to
interactions with cosmic radiation backgrounds. Nevertheless, the isotropic
sub-TeV gamma-ray background observed by the Fermi Large Area Telescope (LAT)
contains indirect information from secondary emission produced in
electromagnetic cascades and constrains hadronic emission scenarios. On the
other hand, observation of PeV gamma-rays would provide a smoking-gun signal
for Galactic emission. In general, the cross-correlation of neutrino emission
with (extended) Galactic and extragalactic gamma-ray sources will serve as the
most sensitive probe for a future identification of neutrino sources.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Ahlers_M/0/1/0/all/0/1">Markus Ahlers</a>A unified picture for low-luminosity and long gamma-ray bursts based on the extended progenitor of llgrb 060218/SN 2006aj. (arXiv:1503.00441v1 [astro-ph.HE])http://arxiv.org/abs/1503.00441
<p>The relation between long gamma-ray bursts (LGRBs) and low-luminosity GRBs
(llgrbs) is a long standing puzzle -- on the one hand their high energy
emission properties are fundamentally different, implying a different gamma-ray
source, yet both are associated with similar supernovae of the same peculiar
type (broad-line Ic), pointing at a similar progenitor and a similar explosion
mechanism. Here we analyze the multi-wavelength data of the particularly
well-observed SN 2006aj, associated with llgrb 060218, finding that its
progenitor star is sheathed in an extended ($&gt;100R_\odot$), low-mass ($\sim
0.01M_\odot$) envelope. This progenitor structure implies that the gamma-ray
emission in this llgrb is generated by a mildly relativistic shock breakout. It
also suggests a unified picture for llgrbs and LGRBs, where the key difference
is the existence of an extended low-mass envelope in llgrbs and its absence in
LGRBs. The same engine, which launches a relativistic jet, can drive the two
explosions, but, while in LGRBs the ultra-relativistic jet emerges from the
bare progenitor star and produces the observed gamma-rays, in llgrbs the
extended envelope smothers the jet and prevents the generation of a large
gamma-ray luminosity. Instead, the jet deposits all its energy in the envelope,
driving a mildly relativistic shock that upon breakout produces a llgrb. In
addition for giving a unified view of the two phenomena, this model provides a
natural explanation to many observed properties of llgrbs. It also implies that
llgrbs are a viable source of the observed extra-galactic diffuse neutrino flux
and that they are promising sources for future gravitational wave detectors.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Nakar_E/0/1/0/all/0/1">Ehud Nakar</a>Inflationary cosmology in modified gravity theories. (arXiv:1503.00442v1 [hep-th])http://arxiv.org/abs/1503.00442
<p>We review inflationary cosmology in modified gravity such as $R^2$ gravity
with its extensions in order to generalize the Starobinsky inflation model. In
particular, we explore inflation realized by three kinds of effects:
modification of gravity, the quantum anomaly, and the $R^2$ term in loop
quantum cosmology. It is explicitly demonstrated that in these inflationary
models, the spectral index of scalar modes of the density perturbations and the
tensor-to-scalar ratio can be consistent with the Planck results. Bounce
cosmology in $F(R)$ gravity is also explained.
</p>
<a href="http://arxiv.org/find/hep-th/1/au:+Bamba_K/0/1/0/all/0/1">Kazuharu Bamba</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Odintsov_S/0/1/0/all/0/1">Sergei D. Odintsov</a>Cosmic-ray induced background intercomparison with actively shielded HPGe detectors at underground locations. (arXiv:1503.00457v1 [physics.ins-det])http://arxiv.org/abs/1503.00457
<p>The main background above 3\,MeV for in-beam nuclear astrophysics studies
with $\gamma$-ray detectors is caused by cosmic-ray induced secondaries. The
two commonly used suppression methods, active and passive shielding, against
this kind of background were formerly considered only as alternatives in
nuclear astrophysics experiments. In this work the study of the effects of
active shielding against cosmic-ray induced events at a medium deep location is
performed. Background spectra were recorded with two actively shielded HPGe
detectors. The experiment was located at 148\,m below the surface of the Earth
in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data
with the same detectors at the Earth's surface, and at depths of 45\,m and
1400\,m, respectively.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Szucs_T/0/1/0/all/0/1">T. Sz&#xfc;cs</a>, <a href="http://arxiv.org/find/physics/1/au:+Bemmerer_D/0/1/0/all/0/1">D. Bemmerer</a>, <a href="http://arxiv.org/find/physics/1/au:+Reinhardt_T/0/1/0/all/0/1">T. P. Reinhardt</a>, <a href="http://arxiv.org/find/physics/1/au:+Schmidt_K/0/1/0/all/0/1">K. Schmidt</a>, <a href="http://arxiv.org/find/physics/1/au:+Takacs_M/0/1/0/all/0/1">M. P. Tak&#xe1;cs</a>, <a href="http://arxiv.org/find/physics/1/au:+Wagner_A/0/1/0/all/0/1">A. Wagner</a>, <a href="http://arxiv.org/find/physics/1/au:+Wagner_L/0/1/0/all/0/1">L. Wagner</a>, <a href="http://arxiv.org/find/physics/1/au:+Weinberger_D/0/1/0/all/0/1">D. Weinberger</a>, <a href="http://arxiv.org/find/physics/1/au:+Zuber_K/0/1/0/all/0/1">K. Zuber</a>Flaring gamma-ray emission from high redshift blazars. (arXiv:1503.00480v1 [astro-ph.HE])http://arxiv.org/abs/1503.00480
<p>High redshift blazars are among the most powerful objects in the Universe.
Although they represent a significant fraction of the extragalactic hard X-ray
sky, they are not commonly detected in gamma-rays. High redshift (z&gt;2) objects
represent &lt;10 per cent of the AGN population observed by Fermi so far, and
gamma-ray flaring activity from these sources is even more uncommon. The
characterization of the radio-to-gamma-ray properties of high redshift blazars
represent a powerful tool for the study of both the energetics of such extreme
objects and the Extragalactic Background Light. We present results of a
multi-band campaign on TXS 0536+145, which is the highest redshift flaring
gamma-ray blazar detected so far. At the peak of the flare the source reached
an apparent isotropic gamma-ray luminosity of 6.6x10^49 erg/s, which is
comparable with the luminosity observed from the most powerful blazars. The
physical properties derived from the multi-wavelength observations are then
compared with those shown by the high redshift population. In addition
preliminary results from the high redshift flaring blazar PKS 2149-306 will be
discussed.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Orienti_M/0/1/0/all/0/1">M. Orienti</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+DAmmando_F/0/1/0/all/0/1">F. D&#x27;Ammando</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Giroletti_M/0/1/0/all/0/1">M. Giroletti</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Dallacasa_D/0/1/0/all/0/1">D. Dallacasa</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Venturi_T/0/1/0/all/0/1">T. Venturi</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Finke_J/0/1/0/all/0/1">J. Finke</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Ajello_M/0/1/0/all/0/1">M. Ajello</a> (4), ((1) INAF-IRA Bologna, (2) University of Bologna, (3) US Naval Research Laboratory, (4) Clemson University)X-ray Emission from Middle-Aged Gamma-Ray Pulsars. (arXiv:1503.00483v1 [astro-ph.HE])http://arxiv.org/abs/1503.00483
<p>Electrons/positrons produced in a pulsar magnetosphere emit synchrotron
radiation, which is widely believed as the origin of the non-thermal X-ray
emission detected from pulsars. Particles are produced by curvature photons
emitted from accelerated particles in the magnetosphere. These curvature
photons are detected as pulsed $\gamma$-ray emissions from pulsars with age
$\lesssim10^6$ yr. Using $\gamma$-ray observations and analytical model, we
impose severe constraints on the synchrotron radiation as a mechanism of the
non-thermal X-ray emission. In most middle-aged pulsars ($\sim10^5-10^6$ yr)
which photon-photon pair production is less efficient in their magnetosphere,
we find that the synchrotron radiation model is difficult to explain the
observed non-thermal X-ray emission.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Kisaka_S/0/1/0/all/0/1">Shota Kisaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_S/0/1/0/all/0/1">Shuta J. Tanaka</a>Inertial-Range Reconnection in Magnetohydrodynamic Turbulence and in the Solar Wind. (arXiv:1503.00509v1 [physics.plasm-ph])http://arxiv.org/abs/1503.00509
<p>In situ spacecraft data on the solar wind show events identified as magnetic
reconnection with outflows and apparent "`$X$-lines" $10^{3-4}$ times ion
scales. To understand the role of turbulence at these scales, we make a case
study of an inertial-range reconnection event in a magnetohydrodynamic (MHD)
simulation. We observe stochastic wandering of field-lines in space, breakdown
of standard magnetic flux-freezing due to Richardson dispersion, and a
broadened reconnection zone containing many current sheets. The coarse-grain
magnetic geometry is like large-scale reconnection in the solar wind, however,
with a hyperbolic flux-tube or "$X$-line" extending over integral
length-scales.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Lalescu_C/0/1/0/all/0/1">Cristian C. Lalescu</a>, <a href="http://arxiv.org/find/physics/1/au:+Shi_Y/0/1/0/all/0/1">Yi-Kang Shi</a>, <a href="http://arxiv.org/find/physics/1/au:+Eyink_G/0/1/0/all/0/1">Gregory L. Eyink</a>, <a href="http://arxiv.org/find/physics/1/au:+Drivas_T/0/1/0/all/0/1">Theodore D. Drivas</a>, <a href="http://arxiv.org/find/physics/1/au:+Vishniac_E/0/1/0/all/0/1">Ethan T. Vishniac</a>, <a href="http://arxiv.org/find/physics/1/au:+Lazarian_A/0/1/0/all/0/1">Alexander Lazarian</a>Constraining supernova equations of state with equilibrium constants from heavy-ion collisions. (arXiv:1503.00518v1 [nucl-th])http://arxiv.org/abs/1503.00518
<p>Cluster formation is a fundamental aspect of the equation of state (EOS) of
warm and dense nuclear matter such as can be found in supernovae (SN). Similar
matter can be studied in heavy-ion collisions (HIC). We use the experimental
data of Qin et al. 2012 to test calculations of cluster formation and the role
of in-medium modifications of cluster properties in SN EOSs. For the comparison
between theory and experiment we use chemical equilibrium constants as the main
observables. This reduces some of the systematic uncertainties and allows
deviations from ideal gas behavior to be identified clearly. In the analysis,
we carefully account for the differences between matter in SN and HIC. We find
that, at the lowest densities, the experiment and all theoretical models are
consistent with the ideal gas behavior. At higher densities ideal behavior is
clearly ruled out and interaction effects have to be considered. The
contributions of continuum correlations are of relevance in the virial
expansion and remain a difficult problem to solve at higher densities. We
conclude that at the densities and temperatures discussed mean-field
interactions of nucleons, inclusion of all relevant light clusters, and a
suppression mechanism of clusters at high densities have to be incorporated in
the SN EOS.
</p>
<a href="http://arxiv.org/find/nucl-th/1/au:+Hempel_M/0/1/0/all/0/1">Matthias Hempel</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Hagel_K/0/1/0/all/0/1">Kris Hagel</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Natowitz_J/0/1/0/all/0/1">Joseph Natowitz</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Ropke_G/0/1/0/all/0/1">Gerd R&#xf6;pke</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Typel_S/0/1/0/all/0/1">Stefan Typel</a>Carbon, nitrogen and $\alpha$-element abundances determine the formation sequence of the Galactic thick and thin disks. (arXiv:1503.00537v1 [astro-ph.SR])http://arxiv.org/abs/1503.00537
<p>Using the DR12 public release of APOGEE data, we show that thin and thick
disk separate very well in the space defined by [$\alpha$/Fe], [Fe/H] and
[C/N]. Thick disk giants have both higher [C/N] and higher [$\alpha$/Fe] than
do thin disk stars with similar [Fe/H]. We deduce that the thick disk is
composed of lower mass stars than the thin disk. Considering the fact that at a
given metallicity there is a one-to-one relation between stellar mass and age,
we are then able to infer the chronology of disk formation. Both the thick and
the thin disks - defined by [$\alpha$/Fe] -- converge in their dependance on
[C/N] and [C+N/Fe] at [Fe/H]$\approx$-0.7. We conclude that 1) the majority of
thick disk stars formed earlier than did the thin disk stars 2) the formation
histories of the thin and thick disks diverged early on, even when the [Fe/H]
abundances are similar 3) that the star formation rate in the thin disk has
been lower than in the thick disk, at all metallicities. Although these general
conclusions remain robust, we also show that current stellar evolution models
cannot reproduce the observed C/N ratios for thick disk stars. Unexpectedly,
reduced or inhibited canonical extra-mixing is very common in field stars.
While subject to abundance calibration zeropoint uncertainties, this implies a
strong dependence of non canonical extra-mixing along the red giant branch on
the initial composition of the star and in particular on the $\alpha$ elemental
abundance.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Masseron_T/0/1/0/all/0/1">T. Masseron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gilmore_G/0/1/0/all/0/1">G. Gilmore</a> (Institute of Astronomy, Cambridge, UK)Calculation of conventional and prompt lepton fluxes at very high energy. (arXiv:1503.00544v1 [hep-ph])http://arxiv.org/abs/1503.00544
<p>An efficient method for calculating inclusive conventional and prompt
atmospheric leptons fluxes is presented. The coupled cascade equations are
solved numerically by formulating them as matrix equation. The presented
approach is very flexible and allows the use of different hadronic interaction
models, realistic parametrizations of the primary cosmic-ray flux and the
Earth's atmosphere, and a detailed treatment of particle interactions and
decays. The power of the developed method is illustrated by calculating lepton
flux predictions for a number of different scenarios.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Fedynitch_A/0/1/0/all/0/1">Anatoli Fedynitch</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Engel_R/0/1/0/all/0/1">Ralph Engel</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Gaisser_T/0/1/0/all/0/1">Thomas K. Gaisser</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Riehn_F/0/1/0/all/0/1">Felix Riehn</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Stanev_T/0/1/0/all/0/1">Todor Stanev</a>Improving the convergence properties of the moving-mesh code AREPO. (arXiv:1503.00562v1 [astro-ph.GA])http://arxiv.org/abs/1503.00562
<p>Accurate numerical solutions of the equations of hydrodynamics play an ever
more important role in many fields of astrophysics. In this work, we
reinvestigate the accuracy of the moving-mesh code \textsc{Arepo} and show how
its convergence order can be improved for general problems. In particular, we
clarify that for certain problems \textsc{Arepo} only reaches first-order
convergence for its original formulation. This can be rectified by simple
modifications we propose to the time integration scheme and the spatial
gradient estimates of the code, both improving the accuracy of the code. We
demonstrate that the new implementation is indeed second-order accurate under
the $L^1$ norm, and in particular substantially improves conservation of
angular momentum. Interestingly, whereas these improvements can significantly
change the results of smooth test problems, we also find that cosmological
simulations of galaxy formation are unaffected, demonstrating that the
numerical errors eliminated by the new formulation do not impact these
simulations. In contrast, simulations of binary stars followed over a large
number of orbital times are strongly affected, as here it is particularly
crucial to avoid a long-term build up of errors in angular momentum
conservation.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Pakmor_R/0/1/0/all/0/1">Ruediger Pakmor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Springel_V/0/1/0/all/0/1">Volker Springel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bauer_A/0/1/0/all/0/1">Andreas Bauer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mocz_P/0/1/0/all/0/1">Philip Mocz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Munoz_D/0/1/0/all/0/1">Diego J. Munoz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohlmann_S/0/1/0/all/0/1">Sebastian T. Ohlmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schaal_K/0/1/0/all/0/1">Kevin Schaal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_C/0/1/0/all/0/1">Chenchon Zhu</a>2.5D global-disk oscillation models of the Be shell star {\zeta} Tauri I. Spectroscopic and polarimetric analysis. (arXiv:1503.00590v1 [astro-ph.SR])http://arxiv.org/abs/1503.00590
<p>Context. Various Be stars exhibit intensity variations of the violet and red
emission peaks in their HI lines observed in emission. This so-called $V/R$
phenomenon is usually explained by the precession of a one-armed spiral density
perturbation in the circumstellar disk. That global-disk oscillation scenario
was confirmed, both observationally and theoretically, in the previous series
of two papers analyzing the Be shell star {\zeta} Tauri. The vertically
averaged (2D) global-disk oscillation model used at the time was able to
reproduce the $V/R$ variations observed in H{\alpha}, as well as the spatially
resolved interferometric data from AMBER/VLTI. Unfortunately, that model failed
to reproduce the $V/R$ phase of Br15 and the amplitude of the polarization
variation, suggesting that the inner disk structure predicted by the model was
incorrect.
</p>
<p>Aims. The first aim of the present paper is to quantify the temporal
variations of the shell-line characteristics of {\zeta} Tauri. The second aim
is to better understand the physics underlying the $V/R$ phenomenon by modeling
the shell-line variations together with the $V/R$ and polarimetric variations.
The third aim is to test a new 2.5D disk oscillation model, which solves the
set of equations that describe the 3D perturbed disk structure but keeps only
the equatorial (i.e., 2D) component of the solution. This approximation was
adopted to allow comparisons with the previous 2D model, and as a first step
toward a future 3D model.
</p>
<p>Results. The new 2.5D formalism improves the agreement with the observed
$V/R$ variations of H{\alpha} and Br15, under the proviso that a large value of
the viscosity parameter, {\alpha} = 0.8, be adopted. Nonetheless, it remains
challenging for the models to reproduce consistently the amplitude and the
average level of the polarization data, whatever formalism is adopted.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Escolano_C/0/1/0/all/0/1">C. Escolano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carciofi_A/0/1/0/all/0/1">A. C. Carciofi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Okazaki_A/0/1/0/all/0/1">A. T. Okazaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rivinius_T/0/1/0/all/0/1">T. Rivinius</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baade_D/0/1/0/all/0/1">D. Baade</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stefl_S/0/1/0/all/0/1">S. Stefl</a>Post-equinox dynamics and polar cloud structure on Uranus. (arXiv:1503.00592v1 [astro-ph.EP])http://arxiv.org/abs/1503.00592
<p>Post equinox imaging of Uranus by HST, Keck, and Gemini telescopes has
enabled new measurements of winds over previously sampled latitudes as well as
measurements at high northern latitudes that have recently come into better
view. These new observations also used techniques to greatly improve signal to
noise ratios, making possible the detection and tracking of more subtle cloud
features. The 250 m/s prograde jet peaking near 60 N was confirmed and more
accurately characterized. Several long-lived cloud features have also been
tracked. The winds pole-ward of 60 N are consistent with solid body rotation at
a westward (prograde) rate of 4.3 deg/h with respect to Uranus' interior. When
combined with 2007 and other recent measurements, it is clear that a small but
well-resolved asymmetry exists in the zonal profile at middle latitudes,
peaking at 35 deg, where southern winds are 20 m/s more westward than
corresponding northern winds. High S/N Keck II imaging of the north polar
region of Uranus reveals a transition from streaky bands below 60 N to a region
from 60 deg to nearly the north pole, where widely distributed small bright
spots, resembling cumulus cloud fields, with several isolated dark spots, are
the dominant style of cloud features. This presents a stark contrast to 2003
detailed views of the south polar region of Uranus when no discrete cloud
features could be detected in comparable Keck II near-IR images. The pressure
levels of discrete clouds estimated from spatial modulations in H and Hcont
images indicate that the polar cloud features are generally in the 1.3 to 2-3
bar range, as are equatorial and several mid-latitude features. Several of the
brighter mid latitude features are found above the 1.2-bar level of methane
condensation.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Sromovsky_L/0/1/0/all/0/1">Lawrence Sromovsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fry_P/0/1/0/all/0/1">Patrick Fry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hammel_H/0/1/0/all/0/1">Heidi Hammel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pater_I/0/1/0/all/0/1">Imke de Pater</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rages_K/0/1/0/all/0/1">Kathy Rages</a>Searches for Time Dependent Neutrino Sources with IceCube Data from 2008 to 2012. (arXiv:1503.00598v1 [astro-ph.HE])http://arxiv.org/abs/1503.00598
<p>In this paper searches for flaring astrophysical neutrino sources and sources
with periodic emission with the IceCube neutrino telescope are presented. In
contrast to time integrated searches, where steady emission is assumed, the
analyses presented here look for a time dependent signal of neutrinos using the
information from the neutrino arrival times to enhance the discovery potential.
A search was performed for correlations between neutrino arrival times and
directions as well as neutrino emission following time dependent lightcurves,
sporadic emission or periodicities of candidate sources. These include active
galactic nuclei, soft $\gamma$-ray repeaters, supernova remnants hosting
pulsars, micro-quasars and X-ray binaries. The work presented here updates and
extends previously published results to a longer period that covers four years
of data from 2008 April 5 to 2012 May 16 including the first year of operation
of the completed 86-string detector. The analyses did not find any significant
time dependent point sources of neutrinos and the results were used to set
upper limits on the neutrino flux from source candidates.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Aartsen_M/0/1/0/all/0/1">M. G. Aartsen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ackermann_M/0/1/0/all/0/1">M. Ackermann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Adams_J/0/1/0/all/0/1">J. Adams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aguilar_J/0/1/0/all/0/1">J. A. Aguilar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ahlers_M/0/1/0/all/0/1">M. Ahlers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ahrens_M/0/1/0/all/0/1">M. Ahrens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altmann_D/0/1/0/all/0/1">D. Altmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anderson_T/0/1/0/all/0/1">T. Anderson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arguelles_C/0/1/0/all/0/1">C. Arguelles</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arlen_T/0/1/0/all/0/1">T. C. Arlen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Auffenberg_J/0/1/0/all/0/1">J. Auffenberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_X/0/1/0/all/0/1">X. Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baker_M/0/1/0/all/0/1">M. Baker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barwick_S/0/1/0/all/0/1">S. W. Barwick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baum_V/0/1/0/all/0/1">V. Baum</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bay_R/0/1/0/all/0/1">R. Bay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beatty_J/0/1/0/all/0/1">J. J. Beatty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tjus_J/0/1/0/all/0/1">J. Becker Tjus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Becker_K/0/1/0/all/0/1">K.-H. Becker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+BenZvi_S/0/1/0/all/0/1">S. BenZvi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berghaus_P/0/1/0/all/0/1">P. Berghaus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berley_D/0/1/0/all/0/1">D. Berley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernardini_E/0/1/0/all/0/1">E. Bernardini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernhard_A/0/1/0/all/0/1">A. Bernhard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Besson_D/0/1/0/all/0/1">D. Z. Besson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Binder_G/0/1/0/all/0/1">G. Binder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bindig_D/0/1/0/all/0/1">D. Bindig</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bissok_M/0/1/0/all/0/1">M. Bissok</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blaufuss_E/0/1/0/all/0/1">E. Blaufuss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blumenthal_J/0/1/0/all/0/1">J. Blumenthal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boersma_D/0/1/0/all/0/1">D. J. Boersma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bohm_C/0/1/0/all/0/1">C. Bohm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bos_F/0/1/0/all/0/1">F. Bos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bose_D/0/1/0/all/0/1">D. Bose</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boser_S/0/1/0/all/0/1">S. B&#xf6;ser</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Botner_O/0/1/0/all/0/1">O. Botner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brayeur_L/0/1/0/all/0/1">L. Brayeur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bretz_H/0/1/0/all/0/1">H.-P. Bretz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brown_A/0/1/0/all/0/1">A. M. Brown</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Buzinsky_N/0/1/0/all/0/1">N. Buzinsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casey_J/0/1/0/all/0/1">J. Casey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casier_M/0/1/0/all/0/1">M. Casier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheung_E/0/1/0/all/0/1">E. Cheung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chirkin_D/0/1/0/all/0/1">D. Chirkin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christov_A/0/1/0/all/0/1">A. Christov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christy_B/0/1/0/all/0/1">B. Christy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_K/0/1/0/all/0/1">K. Clark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Classen_L/0/1/0/all/0/1">L. Classen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clevermann_F/0/1/0/all/0/1">F. Clevermann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coenders_S/0/1/0/all/0/1">S. Coenders</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cowen_D/0/1/0/all/0/1">D. F. Cowen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Silva_A/0/1/0/all/0/1">A. H. Cruz Silva</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Daughhetee_J/0/1/0/all/0/1">J. Daughhetee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davis_J/0/1/0/all/0/1">J. C. Davis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Day_M/0/1/0/all/0/1">M. Day</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andre_J/0/1/0/all/0/1">J. P. A. M. de Andr&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clercq_C/0/1/0/all/0/1">C. De Clercq</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dembinski_H/0/1/0/all/0/1">H. Dembinski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ridder_S/0/1/0/all/0/1">S. De Ridder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Desiati_P/0/1/0/all/0/1">P. Desiati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vries_K/0/1/0/all/0/1">K. D. de Vries</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wasseige_G/0/1/0/all/0/1">G. de Wasseige</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+With_M/0/1/0/all/0/1">M. de With</a>, et al. (244 additional authors not shown)Indirect and direct detection prospect for TeV dark matter in the MSSM-9. (arXiv:1503.00599v1 [hep-ph])http://arxiv.org/abs/1503.00599
<p>We investigate the prospects of indirect and direct dark matter searches
within the minimal supersymmetric standard model with nine parameters (MSSM-9).
These nine parameters include three gaugino masses, Higgs, slepton and squark
masses, all treated independently. We perform a Bayesian Monte Carlo scan of
the parameter space taking into consideration all available particle physics
constraints such as the Higgs mass of 126 GeV, upper limits on the scattering
cross-section from direct-detection experiments, and assuming that the MSSM-9
provides all the dark matter abundance through thermal freeze-out mechanism.
Within this framework we find two most probable regions for dark matter: 1-TeV
higgsino-like and 3-TeV wino-like neutralinos. We discuss prospects for future
indirect (in particular the Cherenkov Telescope Array, CTA) and direct
detection experiments. We find that for slightly contracted dark matter
profiles in our Galaxy, which can be caused by the effects of baryonic infall
in the Galactic center, CTA will be able to probe a large fraction of the
remaining allowed region in synergy with future direct detection experiments
like XENON-1T.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Catalan_M/0/1/0/all/0/1">Maria Eugenia Cabrera Catalan</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ando_S/0/1/0/all/0/1">Shin&#x27;ichiro Ando</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Weniger_C/0/1/0/all/0/1">Christoph Weniger</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Zandanel_F/0/1/0/all/0/1">Fabio Zandanel</a>Galvano-rotational effect in a pulsar induced by the electroweak interaction. (arXiv:1503.00608v1 [hep-ph])http://arxiv.org/abs/1503.00608
<p>We predict the new galvano-rotational effect which consists in the appearance
of the electric current along the axis of the matter rotation. This effect is
caused by the parity violating electroweak interaction between massless charged
particles in the rotating matter. We start with the exact solution of the Dirac
equation for a fermion involved in the electroweak interaction in the rotating
frame. This equation includes the noninertial effects. Then, using the obtained
solution, we derive the induced electric current which turns out to flow along
the rotation axis. We study the possibility of the appearance of the
galvano-rotational effect in dense matter of compact astrophysical objects. The
particular example of neutron and hypothetical quark stars is discussed. It is
shown that, using this effect, one can expect the generation of toroidal
magnetic fields comparable with poloidal ones in old millisecond pulsars. We
also briefly discuss the generation of the magnetic helicity in these stars.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Dvornikov_M/0/1/0/all/0/1">Maxim Dvornikov</a> (University of S&#xe3;o Paulo, IZMIRAN, Tomsk State University)Citizen Science on the Faroe Islands in Advance of an Eclipse. (arXiv:1503.00613v1 [astro-ph.IM])http://arxiv.org/abs/1503.00613
<p>On 2015 March 20, a total solar eclipse will occur in the North Atlantic,
with the Kingdom of Denmark's Faroe Islands and Norway's Svalbard archipelago
(formerly Spitzbergen) being the only options for land-based observing. The
region is known for wild, unpredictable, and often cloudy conditions, which
potentially pose a serious threat for people hoping to view the spectacle.
</p>
<p>We report on a citizen-science, weather-monitoring project, based in the
Faroe Islands, which was conducted in March 2014 - one year prior to the
eclipse. The project aimed to promote awareness of the eclipse among the local
communities, with the data collected providing a quantitative overview of
typical weather conditions that may be expected in 2015. It also allows us to
validate the usefulness of short-term weather forecasts, which may be used to
increase the probability of observing the eclipse.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Sims_G/0/1/0/all/0/1">Geoff Sims</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Russo_K/0/1/0/all/0/1">Kate Russo</a>Millimeter polarisation of the protoplanetary nebula OH 231.8+4.2: A follow-up study with CARMA. (arXiv:1503.00636v1 [astro-ph.SR])http://arxiv.org/abs/1503.00636
<p>In order to investigate the characteristics and influence of the magnetic
field in evolved stars, we performed a follow-up investigation of our previous
submillimeter analysis of the proto-planetary nebula (PPN) OH 231.8+4.2 (Sabin
et al. 2014), this time at 1.3mm with the CARMA facility in polarisation mode
for the purpose of a multi-scale analysis. OH 231.8+4.2 was observed at ~2.5"
resolution and we detected polarised emission above the 3-sigma threshold (with
a mean polarisation fraction of 3.5 %). The polarisation map indicates an
overall organised magnetic field within the nebula. The main finding in this
paper is the presence of a structure mostly compatible with an ordered toroidal
component that is aligned with the PPN's dark lane. We also present some
alternative magnetic field configuration to explain the structure observed.
These data complete our previous SMA submillimeter data for a better
investigation and understanding of the magnetic field structure in OH
231.8+4.2.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Sabin_L/0/1/0/all/0/1">L. Sabin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hull_C/0/1/0/all/0/1">C.L.H. Hull</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Plambeck_R/0/1/0/all/0/1">R.L. Plambeck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zijlstra_A/0/1/0/all/0/1">A.A. Zijlstra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vazquez_R/0/1/0/all/0/1">R. V&#xe1;zquez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Navarro_S/0/1/0/all/0/1">S.G. Navarro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guillen_P/0/1/0/all/0/1">P.F. Guill&#xe9;n</a>A compression scheme for radio data in high performance computing. (arXiv:1503.00638v1 [astro-ph.IM])http://arxiv.org/abs/1503.00638
<p>We present a procedure for efficiently compressing astronomical radio data
for high performance applications. Integrated, post-correlation data are first
passed through a nearly lossless rounding step which compares the precision of
the data to a generalized and calibration-independent form of the radiometer
equation. This allows the precision of the data to be reduced in a way that has
an insignificant impact on the data. The newly developed Bitshuffle lossless
compression algorithm is subsequently applied. When the algorithm is used in
conjunction with the HDF5 library and data format, data produced by the CHIME
Pathfinder telescope is compressed to 28% of its original size and
decompression throughputs in excess of 1 GB/s are obtained on a single core.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Masui_K/0/1/0/all/0/1">Kiyoshi Masui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amiri_M/0/1/0/all/0/1">Mandana Amiri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Connor_L/0/1/0/all/0/1">Liam Connor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deng_M/0/1/0/all/0/1">Meiling Deng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fandino_M/0/1/0/all/0/1">Mateus Fandino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hofer_C/0/1/0/all/0/1">Carolin H&#xf6;fer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Halpern_M/0/1/0/all/0/1">Mark Halpern</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hanna_D/0/1/0/all/0/1">David Hanna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hincks_A/0/1/0/all/0/1">Adam D. Hincks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hinshaw_G/0/1/0/all/0/1">Gary Hinshaw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parra_J/0/1/0/all/0/1">Juan Mena Parra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Newburgh_L/0/1/0/all/0/1">Laura B. Newburgh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shaw_J/0/1/0/all/0/1">J. Richard Shaw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vanderlinde_K/0/1/0/all/0/1">Keith Vanderlinde</a>Powerful radiative jets in super-critical accretion disks around non-spinning black holes. (arXiv:1503.00654v1 [astro-ph.HE])http://arxiv.org/abs/1503.00654
<p>We describe a set of simulations of super-critical accretion onto a
non-rotating supermassive BH. The accretion flow is radiation pressure
dominated and takes the form of a geometrically thick disk with twin
low-density funnels around the rotation axis. For accretion rates $\gtrsim 10
\dot M_{\rm Edd}$, there is sufficient gas in the funnel to make this region
optically thick. Radiation from the disk first flows into the funnel, after
which it accelerates the optically thick funnel gas along the axis. The
resulting jet is baryon-loaded and has a terminal density-weighted velocity
$\approx 0.3c$. Much of the radiative luminosity is converted into kinetic
energy by the time the escaping gas becomes optically thin. For an observer
viewing down the axis, the isotropic equivalent luminosity of total energy is
as much as $10^{48}\,\rm erg\,s^{-1}$ for a $10^7 M_\odot$ BH accreting at
$10^3$ Eddington. Therefore, energetically, the simulated jets are consistent
with observations of the most powerful tidal disruption events, e.g., Swift
J1644. The jet velocity is, however, too low to match the Lorentz factor
$\gamma &gt; 2$ inferred in J1644. There is no such conflict in the case of other
tidal disruption events. Since favorably oriented observers see isotropic
equivalent luminosities that are highly super-Eddington, the simulated models
can explain observations of ultra-luminous X-ray sources, at least in terms of
luminosity and energetics, without requiring intermediate mass black holes.
Finally, since the simulated jets are baryon-loaded and have mildly
relativistic velocities, they match well the jets observed in SS433. The latter
are, however, more collimated than the simulated jets. This suggests that, even
if magnetic fields are not important for acceleration, they may perhaps still
play a role in confining the jet.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Sadowski_A/0/1/0/all/0/1">Aleksander Sadowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Narayan_R/0/1/0/all/0/1">Ramesh Narayan</a>SDSSJ14584479+3720215: A Benchmark JHK Blazar Light Curve from the 2MASS Calibration Scans. (arXiv:1503.00657v1 [astro-ph.HE])http://arxiv.org/abs/1503.00657
<p>Active galactic nuclei (AGNs) are well-known to exhibit flux variability
across a wide range of wavelength regimes, but the precise origin of the
variability at different wavelengths remains unclear. To investigate the
relatively unexplored near-IR variability of the most luminous AGNs, we conduct
a search for variability using well sampled JHKs-band light curves from the
2MASS survey calibration fields. Our sample includes 27 known quasars with an
average of 924 epochs of observation over three years, as well as one
spectroscopically confirmed blazar (SDSSJ14584479+3720215) with 1972 epochs of
data. This is the best-sampled NIR photometric blazar light curve to date, and
it exhibits correlated, stochastic variability that we characterize with
continuous auto-regressive moving average (CARMA) models. None of the other 26
known quasars had detectable variability in the 2MASS bands above the
photometric uncertainty. A blind search of the 2MASS calibration field light
curves for AGN candidates based on fitting CARMA(1,0) models (damped-random
walk) uncovered only 7 candidates. All 7 were young stellar objects within the
{\rho} Ophiuchus star forming region, five with previous X-ray detections. A
significant {\gamma}-ray detection (5{\sigma}) for the known blazar using 4.5
years of Fermi photon data is also found. We suggest that strong NIR
variability of blazars, such as seen for SDSSJ14584479+3720215, can be used as
an efficient method of identifying previously-unidentified {\gamma}-ray
blazars, with low contamination from other AGN.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Davenport_J/0/1/0/all/0/1">James R. A. Davenport</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ruan_J/0/1/0/all/0/1">John J. Ruan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Becker_A/0/1/0/all/0/1">Andrew C. Becker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Macleod_C/0/1/0/all/0/1">Chelsea L. Macleod</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cutri_R/0/1/0/all/0/1">Roc M. Cutri</a>Constraining the Mass and the Non-Radial Drag Coefficient of a Solar Coronal Mass Ejection. (arXiv:1503.00664v1 [astro-ph.SR])http://arxiv.org/abs/1503.00664
<p>Decades of observations show that CMEs can deflect from a purely radial
trajectory yet no consensus exists as to the cause of these deflections. Many
of theories attribute the CME deflection to magnetic forces. We developed
ForeCAT (Kay et al. 2013, Kay et al. 2015), a model for CME deflections based
solely on magnetic forces, neglecting any reconnection effects. Here we compare
ForeCAT predictions to the observed deflection of the 2008 December 12 CME and
find that ForeCAT can accurately reproduce the observations. Multiple
observations show that this CME deflected nearly 30{\deg} in latitude (Byrne et
al. 2010, Gui et al. 2011) and 4.4{\deg} in longitude (Gui et al. 2011). From
the observations, we are able to constrain all of the ForeCAT input parameters
(initial position, radial propagation speed, and expansion) except the CME mass
and the drag coefficient that affects the CME motion. By minimizing the reduced
chi-squared, $\chi^2_{\nu}$, between the ForeCAT results and the observations
we determine an acceptable mass range between 4.5x10$^{14}$ and 1x10$^{15}$ g
and the drag coefficient less than 1.4 with a best fit at 7.5x10$^{14}$ g and 0
for the mass and drag coefficient. ForeCAT is sensitive to the magnetic
background and we are also able to constrain the rate at which the quiet sun
magnetic field falls to be similar or to or fall slightly slower than the
Potential Field Source Surface model.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Kay_C/0/1/0/all/0/1">C. Kay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Santos_L/0/1/0/all/0/1">L. F. G. dos Santos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Opher_M/0/1/0/all/0/1">M. Opher</a>One of the closest planet pairs to the 3:2 Mean Motion Resonance, confirmed with K2 observations and Transit Timing Variations: EPIC201505350. (arXiv:1503.00692v1 [astro-ph.EP])http://arxiv.org/abs/1503.00692
<p>The K2 mission has recently begun to discover new and diverse planetary
systems. In December 2014 Campaign 1 data from the mission was released,
providing high-precision photometry for ~22000 objects over an 80 day timespan.
We searched these data with the aim of detecting further important new objects.
Our search through two separate pipelines led to the independent discovery of
EPIC201505350, a two-planet system of Neptune sized objects (4.2 and 7.2
$R_\oplus$), orbiting a K dwarf extremely close to the 3:2 mean motion
resonance. The two planets each show transits, sometimes simultaneously due to
their proximity to resonance and alignment of conjunctions. We obtain further
ground based photometry of the larger planet with the NITES telescope,
demonstrating the presence of large transit timing variations (TTVs) of over an
hour. These TTVs allows us to confirm the planetary nature of the system, and
place a limit on the mass of the outer planet of $386M_\oplus$.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Armstrong_D/0/1/0/all/0/1">David J. Armstrong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Veras_D/0/1/0/all/0/1">Dimitri Veras</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barros_S/0/1/0/all/0/1">Susana C. C. Barros</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Demangeon_O/0/1/0/all/0/1">Olivier Demangeon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McCormac_J/0/1/0/all/0/1">James McCormac</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Osborn_H/0/1/0/all/0/1">Hugh P. Osborn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lillo_Box_J/0/1/0/all/0/1">Jorge Lillo-Box</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Santerne_A/0/1/0/all/0/1">Alexandre Santerne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsantaki_M/0/1/0/all/0/1">Maria Tsantaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Almenara_J/0/1/0/all/0/1">Jos&#xe9;-Manuel Almenara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barrado_D/0/1/0/all/0/1">David Barrado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boisse_I/0/1/0/all/0/1">Isabelle Boisse</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bonomo_A/0/1/0/all/0/1">Aldo S. Bonomo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouchy_F/0/1/0/all/0/1">Fran&#xe7;ois Bouchy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brown_D/0/1/0/all/0/1">David J. A. Brown</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bruno_G/0/1/0/all/0/1">Giovanni Bruno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cerda_J/0/1/0/all/0/1">Javiera Rey Cerda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Courcol_B/0/1/0/all/0/1">Bastien Courcol</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deleuil_M/0/1/0/all/0/1">Magali Deleuil</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diaz_R/0/1/0/all/0/1">Rodrigo F. D&#xed;az</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Doyle_A/0/1/0/all/0/1">Amanda P. Doyle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hebrard_G/0/1/0/all/0/1">Guillaume H&#xe9;brard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kirk_J/0/1/0/all/0/1">James Kirk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lam_K/0/1/0/all/0/1">Kristine W. F. Lam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pollacco_D/0/1/0/all/0/1">Don L. Pollacco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rajpurohit_A/0/1/0/all/0/1">Arvind Rajpurohit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spake_J/0/1/0/all/0/1">Jessica Spake</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walker_S/0/1/0/all/0/1">Simon R. Walker</a>Predicted Impacts of Proton Temperature Anisotropy on Solar Wind Turbulence. (arXiv:1503.00695v1 [physics.space-ph])http://arxiv.org/abs/1503.00695
<p>Particle velocity distributions measured in the weakly collisional solar wind
are frequently found to be non-Maxwellian, but how these non-Maxwellian
distributions impact the physics of plasma turbulence in the solar wind remains
unanswered. Using numerical solutions of the linear dispersion relation for a
collisionless plasma with a bi-Maxwellian proton velocity distribution, we
present a unified framework for the four proton temperature anisotropy
instabilities, identifying the associated stable eigenmodes, highlighting the
unstable region of wavevector space, and presenting the properties of the
growing eigenfunctions. Based on physical intuition gained from this framework,
we address how the proton temperature anisotropy impacts the nonlinear dynamics
of the \Alfvenic fluctuations underlying the dominant cascade of energy from
large to small scales and how the fluctuations driven by proton temperature
anisotropy instabilities interact nonlinearly with each other and with the
fluctuations of the large-scale cascade. We find that the nonlinear dynamics of
the large-scale cascade is insensitive to the proton temperature anisotropy,
and that the instability-driven fluctuations are unlikely to cause significant
nonlinear evolution of either the instability-driven fluctuations or the
turbulent fluctuations of the large-scale cascade.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Klein_K/0/1/0/all/0/1">Kristopher G Klein</a>, <a href="http://arxiv.org/find/physics/1/au:+Howes_G/0/1/0/all/0/1">Gregory G Howes</a>Better Than Earth. (arXiv:1503.00701v1 [astro-ph.EP])http://arxiv.org/abs/1503.00701
<p>Do We Inhabit The Best O All Possible Worlds? German mathematician Gottfried
Leibniz thought so, writing in 1710 that our planet, warts and all, must be the
most optimal one imaginable. Leibniz's idea was roundly scorned as unscientific
wishful thinking, most notably by French author Voltaire in his magnum opus,
Candide. Yet Leibniz might find sympathy from at least one group of scientists
- the astronomers who have for decades treated Earth as a golden standard as
they search for worlds beyond our own solar system. Because earthlings still
know of just one living world - our own - it makes some sense to use Earth as a
template in the search for life elsewhere, such as in the most Earth-like
regions of Mars or Jupiter's watery moon Europa. Now, however, discoveries of
potentially habitable planets orbiting stars other than our sun - exoplanets,
that is - are challenging that geocentric approach.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Heller_R/0/1/0/all/0/1">Ren&#xe9; Heller</a>Absorption Coefficients of the Methane-Nitrogen Binary Ice System: Implications for Pluto. (arXiv:1503.00703v1 [astro-ph.EP])http://arxiv.org/abs/1503.00703
<p>The methane-nitrogen phase diagram of Prokhvatilov and Yantsevich (1983)
indicates that at temperatures relevant to the surfaces of icy dwarf planets
like Pluto, two phases contribute to the methane absorptions: nitrogen
saturated with methane $\bf{\bar{N_{2}}}$:CH$_{4}$ and methane saturated with
nitrogen $\bf{\bar{CH_{4}}}$:N$_{2}$. No optical constants are available so far
for the latter component limiting construction of a proper model, in compliance
with thermodynamic equilibrium considerations. New optical constants for solid
solutions of methane diluted in nitrogen (N$_{2}$:CH$_{4}$) and nitrogen
diluted in methane (CH$_{4}$:N$_{2}$) are presented at temperatures between 40
and 90 K, in the wavelength range 1.1-2.7 $\mu$m at different mixing ratios.
These optical constants are derived from transmission measurements of crystals
grown from the liquid phase in closed cells. A systematic study of the changes
of methane and nitrogen solid mixtures spectral behavior with mixing ratio and
temperature is presented.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Protopapa_S/0/1/0/all/0/1">S. Protopapa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grundy_W/0/1/0/all/0/1">W.M. Grundy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tegler_S/0/1/0/all/0/1">S.C. Tegler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bergonio_J/0/1/0/all/0/1">J.M. Bergonio</a>Multi-wavelength Observations of the Giant X-ray Flare Galaxy NGC 5905: signatures of tidal disruption. (arXiv:1304.2235v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1304.2235
<p>NGC 5905 is one of the few galaxies with no prior evidence for an AGN in
which an X-ray flare, due to the tidal disruption of a star by the massive
black hole in the center of the galaxy, was detected by the RASS in 1990-91.
Here we present analysis of late-time follow-up observations of NGC 5905 using
Chandra, Spitzer VLA 3 GHz and 8 GHz archival data and GMRT 1.28 GHz radio
observations. The X-ray image shows no compact source that could be associated
with an AGN. Instead, the emission is extended -- likely due to nuclear star
formation and the total measured X-ray luminosity is comparable to the X-ray
luminosity determined from the 2002 Chandra observations. Diffuse X-ray
emission was detected close to the circum-nuclear star forming ring. The
Spitzer 2006 mid-infrared spectrum also shows strong evidence of nuclear star
formation but no clear AGN signatures. The semi-analytical models of Tommasin
et. al. 2010 together with the measured [OIV]/[NeII] line ratio suggest that at
most only 5.6% of the total IR Flux at 19 $\mu$m is being contributed by the
AGN. The GMRT 1.28 GHz observations reveal a nuclear source. In the much higher
resolution VLA 3 GHz map, the emission has a double lobed structure of size
2.7'' due to the circumnuclear star forming ring. The GMRT 1.28 GHz peak
emission coincides with the center of the circumnuclear ring. We did not detect
any emission in the VLA 8 GHz (1996) archival data. The 3 $\sigma$ upper limits
for the radio afterglow of the TDE at 1.28 GHz, 3 GHz and 8 GHz are 0.17 mJy,
0.09 mJy and 0.09 mJy, respectively. Our studies thus show that (i) NGC 5905
has a declining X-ray flux consistent with a TDE, (ii) the IR flux is dominated
by nuclear star formation, (iii) the nuclear radio emission observed from the
galaxy is due to circumnuclear star formation, (iv) no compact radio emission
associated with a radio afterglow from the TDE is detected.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Raichur_H/0/1/0/all/0/1">H.Raichur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Das_M/0/1/0/all/0/1">M.Das</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Herrero_A/0/1/0/all/0/1">A.Alonso Herrero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shastri_P/0/1/0/all/0/1">P.Shastri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kantharia_N/0/1/0/all/0/1">N.G.Kantharia</a>Topology and field strength in spherical, anelastic dynamo simulations. (arXiv:1312.7364v2 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1312.7364
<p>Numerical modelling of convection driven dynamos in the Boussinesq
approximation revealed fundamental characteristics of the dynamo-generated
magnetic fields and the fluid flow. Because these results were obtained for an
incompressible fluid, their validity for gas planets and stars remains to be
assessed. A common approach is to take some density stratification into account
with the so-called anelastic approximation. The validity of previous results
obtained in the Boussinesq approximation is tested for anelastic models. We
point out and explain specific differences between both types of models, in
particular with respect to the field geometry and the field strength, but we
also compare scaling laws for the velocity amplitude, the magnetic dissipation
time, and the convective heat flux. Our investigation is based on a systematic
parameter study of spherical dynamo models in the anelastic approximation. We
make use of a recently developed numerical solver and provide results for the
test cases of the anelastic dynamo benchmark. The dichotomy of dipolar and
multipolar dynamos identified in Boussinesq simulations is also present in our
sample of anelastic models. Dipolar models require that the typical length
scale of convection is an order of magnitude larger than the Rossby radius.
However, the distinction between both classes of models is somewhat less
explicit than in previous studies. This is mainly due to two reasons: we found
a number of models with a considerable equatorial dipole contribution and an
intermediate overall dipole field strength. Furthermore, a large density
stratification may hamper the generation of dipole dominated magnetic fields.
Previously proposed scaling laws, such as those for the field strength, are
similarly applicable to anelastic models. It is not clear, however, if this
consistency necessarily implies similar dynamo processes in both settings.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Schrinner_M/0/1/0/all/0/1">M. Schrinner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petitdemange_L/0/1/0/all/0/1">L. Petitdemange</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raynaud_R/0/1/0/all/0/1">R. Raynaud</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dormy_E/0/1/0/all/0/1">E. Dormy</a>Collective electronic pulsation around giant nuclei in the Thomas-Fermi model. (arXiv:1402.3468v4 [physics.plasm-ph] UPDATED)http://arxiv.org/abs/1402.3468
<p>Based on the Thomas-Fermi solution for compressed electron gas around a giant
nucleus, $Z\approx 10^6$, we study electric pulsations of electron
number-density, pressure and electric fields, which could be caused by an
external perturbations acting on the nucleus or the electrons themselves. We
numerically obtain the eigen-frequencies and eigen-functions for stationary
pulsation modes that fulfill the boundary-value problem established by
electron-number and energy-momentum conservation, equation of state, laws of
thermodynamics, and Maxwell's equations, as well as physical boundary
conditions. We choose a proton number of $Z=10^6$ and assume the nucleons in
$\beta$-equilibrium at nuclear density. Similar systems with non-spherical
geometry are hypothesized to exist in the lower crust of neutron stars,
commonly referred to as \textit{pasta equation of state}. The lowest modes turn
out to be heavily influenced by the relativistic plasma frequency induced by
the positive charge background in the nucleus. We discuss the possibility to
apply our results to dynamic nuclei using the spectral method and mention
mechanisms that could stimulate such dynamics in the astrophysical context.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Ludwig_H/0/1/0/all/0/1">Hendrik Ludwig</a>, <a href="http://arxiv.org/find/physics/1/au:+Ruffini_R/0/1/0/all/0/1">Remo Ruffini</a>, <a href="http://arxiv.org/find/physics/1/au:+Xue_S/0/1/0/all/0/1">She-Sheng Xue</a>Constraining Majorana CP Phase in Precision Era of Cosmology and Double Beta Decay Experiment. (arXiv:1402.6014v2 [hep-ph] UPDATED)http://arxiv.org/abs/1402.6014
<p>We show that precision measurement of (1) sum of neutrino masses by
cosmological observation and (2) lifetime of neutrinoless double beta decay in
ton-scale experiments, with supplementary use of (3) effective mass measured in
single beta decay experiment, would allow us to obtain information on the
Majorana phase of neutrinos. To quantify the sensitivity to the phase we use
the CP exclusion fraction, a fraction of the CP phase parameter space that can
be excluded for a given set of assumed input parameters, a global measure for
CP violation. We illustrate the sensitivity under varying assumptions, from
modest to optimistic ones, on experimental errors and theoretical uncertainty
of nuclear matrix elements. Assuming that the latter can be reduced to a factor
of ~1.5 we find that one of the two Majorana phases (denoted as alpha_(21)) can
be constrained by excluding ~10-40% of the phase space at 2sigma CL even with
the modest choice of experimental error for the lowest neutrino mass of 0.1 eV.
The characteristic features of the sensitivity to alpha_(21), such as
dependences on the true values of alpha_(21), are addressed.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Minakata_H/0/1/0/all/0/1">Hisakazu Minakata</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Nunokawa_H/0/1/0/all/0/1">Hiroshi Nunokawa</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Quiroga_A/0/1/0/all/0/1">Alexander A. Quiroga</a>Constraints on cosmological parameters in power-law cosmology. (arXiv:1404.6522v3 [gr-qc] UPDATED)http://arxiv.org/abs/1404.6522
<p>In this paper, we examine observational constraints on the power law
cosmology; essentially dependent on two parameters $H_0$ (Hubble constant) and
$q$ (deceleration parameter). We investigate the constraints on these
parameters using the latest 28 points of H(z) data and 580 points of Union2.1
compilation data and, compare the results with the results of $\Lambda$CDM. We
also forecast constraints using a simulated data set for the future JDEM,
supernovae survey. Our studies give better insight into power law cosmology
than the earlier done analysis by Kumar [<a href="/abs/1109.6924">arXiv:1109.6924</a>] indicating it tuning
well with Union2.1 compilation data but not with H(z) data. However, the
constraints obtained on $&lt;H_0&gt;$ and $&lt;q&gt;$ i.e. $H_0$ average and $q$ average
using the simulated data set for the future JDEM, supernovae survey are found
to be inconsistent with the values obtained from the H(z) and Union2.1
compilation data. We also perform the statefinder analysis and find that the
power-law cosmological models approach the standard $\Lambda$CDM model as
$q\rightarrow -1$. Finally, we observe that although the power law cosmology
explains several prominent features of evolution of the Universe, it fails in
details.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Rani_S/0/1/0/all/0/1">Sarita Rani</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Altaibayeva_A/0/1/0/all/0/1">A. Altaibayeva</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Shahalam_M/0/1/0/all/0/1">M. Shahalam</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Singh_J/0/1/0/all/0/1">J. K. Singh</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Myrzakulov_R/0/1/0/all/0/1">R. Myrzakulov</a>Generating $\fnl$ at $\ell\lsim 60$. (arXiv:1405.3562v3 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1405.3562
<p>The CMB anisotropy at $\ell\lsim 60$ seems to have some special features
which include (i) a dipole modulation and (ii) a decrease in power. It is known
that both of these effects can be generated if a curvaton-type field has a
super-horizon perturbation.
</p>
<p>It is also known that this will generate non-gaussianity $\fnl$ in the same
range of $\ell$, whose magnitude has a lower bound coming from the magnitude of
the observed CMB quadrupole. I revisit that bound in the present paper, and
point out that it may or may not be compatible with current data which should
therefore be re-analysed.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Lyth_D/0/1/0/all/0/1">David H. Lyth</a>Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data. (arXiv:1405.4285v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1405.4285
<p>We measure the weak-lensing masses and galaxy distributions of four massive
galaxy clusters observed during the Science Verification phase of the Dark
Energy Survey. This pathfinder study is meant to 1) validate the DECam imager
for the task of measuring weak-lensing shapes, and 2) utilize DECam's large
field of view to map out the clusters and their environments over 90 arcmin. We
conduct a series of rigorous tests on astrometry, photometry, image quality,
PSF modeling, and shear measurement accuracy to single out flaws in the data
and also to identify the optimal data processing steps and parameters. We find
Science Verification data from DECam to be suitable for the lensing analysis
described in this paper. The PSF is generally well-behaved, but the modeling is
rendered difficult by a flux-dependent PSF width and ellipticity. We employ
photometric redshifts to distinguish between foreground and background
galaxies, and a red-sequence cluster finder to provide cluster richness
estimates and cluster-galaxy distributions. By fitting NFW profiles to the
clusters in this study, we determine weak-lensing masses that are in agreement
with previous work. For Abell 3261, we provide the first estimates of redshift,
weak-lensing mass, and richness. In addition, the cluster-galaxy distributions
indicate the presence of filamentary structures attached to 1E 0657-56 and RXC
J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc),
showcasing the potential of DECam and DES for detailed studies of degree-scale
features on the sky.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Melchior_P/0/1/0/all/0/1">P. Melchior</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suchyta_E/0/1/0/all/0/1">E. Suchyta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huff_E/0/1/0/all/0/1">E. Huff</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirsch_M/0/1/0/all/0/1">M. Hirsch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kacprzak_T/0/1/0/all/0/1">T. Kacprzak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rykoff_E/0/1/0/all/0/1">E. Rykoff</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gruen_D/0/1/0/all/0/1">D. Gruen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Armstrong_R/0/1/0/all/0/1">R. Armstrong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bacon_D/0/1/0/all/0/1">D. Bacon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bechtol_K/0/1/0/all/0/1">K. Bechtol</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernstein_G/0/1/0/all/0/1">G. M. Bernstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bridle_S/0/1/0/all/0/1">S. Bridle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clampitt_J/0/1/0/all/0/1">J. Clampitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Honscheid_K/0/1/0/all/0/1">K. Honscheid</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jain_B/0/1/0/all/0/1">B. Jain</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jouvel_S/0/1/0/all/0/1">S. Jouvel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krause_E/0/1/0/all/0/1">E. Krause</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_H/0/1/0/all/0/1">H. Lin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacCrann_N/0/1/0/all/0/1">N. MacCrann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Patton_K/0/1/0/all/0/1">K. Patton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Plazas_A/0/1/0/all/0/1">A. Plazas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rowe_B/0/1/0/all/0/1">B. Rowe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vikram_V/0/1/0/all/0/1">V. Vikram</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilcox_H/0/1/0/all/0/1">H. Wilcox</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Young_J/0/1/0/all/0/1">J. Young</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zuntz_J/0/1/0/all/0/1">J. Zuntz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abbott_T/0/1/0/all/0/1">T. Abbott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abdalla_F/0/1/0/all/0/1">F. B. Abdalla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Allam_S/0/1/0/all/0/1">S. S. Allam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Banerji_M/0/1/0/all/0/1">M. Banerji</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernstein_J/0/1/0/all/0/1">J. P. Bernstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bernstein_R/0/1/0/all/0/1">R. A. Bernstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bertin_E/0/1/0/all/0/1">E. Bertin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Buckley_Geer_E/0/1/0/all/0/1">E. Buckley-Geer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burke_D/0/1/0/all/0/1">D. L. Burke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Castander_F/0/1/0/all/0/1">F. J. Castander</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Costa_L/0/1/0/all/0/1">L. N. da Costa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cunha_C/0/1/0/all/0/1">C. E. Cunha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Depoy_D/0/1/0/all/0/1">D. L. Depoy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Desai_S/0/1/0/all/0/1">S. Desai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diehl_H/0/1/0/all/0/1">H. T. Diehl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Doel_P/0/1/0/all/0/1">P. Doel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Estrada_J/0/1/0/all/0/1">J. Estrada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evrard_A/0/1/0/all/0/1">A. E. Evrard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Neto_A/0/1/0/all/0/1">A. Fausti Neto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fernandez_E/0/1/0/all/0/1">E. Fernandez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Finley_D/0/1/0/all/0/1">D. A. Finley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Flaugher_B/0/1/0/all/0/1">B. Flaugher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Frieman_J/0/1/0/all/0/1">J. A. Frieman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaztanaga_E/0/1/0/all/0/1">E. Gaztanaga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gerdes_D/0/1/0/all/0/1">D. Gerdes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gruendl_R/0/1/0/all/0/1">R. A. Gruendl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gutierrez_G/0/1/0/all/0/1">G. R. Gutierrez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jarvis_M/0/1/0/all/0/1">M. Jarvis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karliner_I/0/1/0/all/0/1">I. Karliner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kent_S/0/1/0/all/0/1">S. Kent</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuehn_K/0/1/0/all/0/1">K. Kuehn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuropatkin_N/0/1/0/all/0/1">N. Kuropatkin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lahav_O/0/1/0/all/0/1">O. Lahav</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maia_M/0/1/0/all/0/1">M. A. G. Maia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Makler_M/0/1/0/all/0/1">M. Makler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marriner_J/0/1/0/all/0/1">J. Marriner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marshall_J/0/1/0/all/0/1">J. L. Marshall</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Merritt_K/0/1/0/all/0/1">K. W. Merritt</a>, et al. (28 additional authors not shown)Star formation history, dust attenuation and extragalactic background light. (arXiv:1405.7038v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1405.7038
<p>At any given epoch, the Extragalactic Background Light (EBL) carries imprints
of integrated star formation activities in the universe till that epoch. On the
other hand, in order to estimate the EBL, when direct observations are not
possible, one requires an accurate estimation of the star formation rate
density (SFRD) and the dust attenuation ($A_\nu$) in galaxies. Here, we present
a 'progressive fitting method' that determines global average SFRD($z$) and
$A_\nu(z)$ for any given extinction curve by using the available
multi-wavelength multi-epoch galaxy luminosity function measurements. Using the
available observations, we determine the best fitted combinations of SFRD($z$)
and $A_\nu(z)$, in a simple fitting form, up to $z\sim8$ for five well known
extinction curves. We find, irrespective of the extinction curve used, the $z$
at which the SFRD($z$) peaks is higher than the $z$ above which $A_\nu(z)$
begins to decline. For each case, we compute the EBL from ultra-violet to the
far-infrared and optical depth ($\tau_\gamma$) encountered by the high energy
$\gamma$-rays due to pair production upon collisions with these EBL photons. We
compare these with measurements of the local EBL, $\gamma$-ray horizon and
$\tau_\gamma$ measurements using Fermi-LAT. All these and the comparison of
independent SFRD($z$) and $A_\nu(z)$ measurements from the literature with our
predictions favor the extinction curve similar to that of Large Magellanic
Cloud Supershell.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Khaire_V/0/1/0/all/0/1">Vikram Khaire</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Srianand_R/0/1/0/all/0/1">Raghunathan Srianand</a>The Relationship between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High Resolution Hinode Observations. (arXiv:1406.1683v3 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1406.1683
<p>By using high-resolution observations of nearly co-temporal and co-spatial
Solar Optical Telescope spectropolarimeter and X-Ray Telescope coronal X-ray
data onboard Hinode, we revisit the problematic relationship between global
magnetic quantities and coronal X-ray brightness. Co-aligned vector magnetogram
and X-ray data were used for this study. The total X-ray brightness over active
regions is well correlated with integrated magnetic quantities such as the
total unsigned magnetic flux, the total unsigned vertical current, and the
area-integrated square of the vertical and horizontal magnetic fields. On
accounting for the inter-dependence of the magnetic quantities, we inferred
that the total magnetic flux is the primary determinant of the observed
integrated X-ray brightness. Our observations indicate that a stronger coronal
X-ray flux is not related to a higher non-potentiality of active-region
magnetic fields. The data even suggest a slightly negative correlation between
X-ray brightness and a proxy of active-region non-potentiality. Although there
are small numerical differences in the established correlations, the main
conclusions are qualitatively consistent over two different X-ray filters, the
Al-poly and Ti-poly filters, which confirms the strength of our conclusions and
validate and extend earlier studies that used low-resolution data. We discuss
the implications of our results and the constraints they set on theories of
solar coronal heating.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Hazra_S/0/1/0/all/0/1">Soumitra Hazra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nandy_D/0/1/0/all/0/1">Dibyendu Nandy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ravindra_B/0/1/0/all/0/1">B. Ravindra</a>Zero average values of cosmological perturbations as an indispensable condition for the theory and simulations. (arXiv:1407.3244v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1407.3244
<p>We point out a weak side of the commonly used determination of scalar
cosmological perturbations lying in the fact that their average values can be
nonzero for some matter distributions. It is shown that introduction of the
finite-range gravitational potential instead of the infinite-range one resolves
this problem. The concrete illustrative density profile is investigated in
detail in this connection.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Eingorn_M/0/1/0/all/0/1">Maxim Eingorn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brilenkov_M/0/1/0/all/0/1">Maxim Brilenkov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vlahovic_B/0/1/0/all/0/1">Branislav Vlahovic</a>Doppler Shift of the de Broglie Waves- Some New Results from Very Old Concepts. (arXiv:1408.3538v2 [cond-mat.quant-gas] UPDATED)http://arxiv.org/abs/1408.3538
<p>The Doppler shift of de Broglie wave is obtained for fermions and massive
bosons using the conventional form of Lorentz transformations for momentum and
energy of the particles. A formalism is developed to obtain the variation of
wave length for de Broglie waves with temperature for individual particles
using the classic idea of Wien in a many body Fermi gas or massive Bose gas.
</p>
<a href="http://arxiv.org/find/cond-mat/1/au:+De_S/0/1/0/all/0/1">Sanchari De</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Chakrabarty_S/0/1/0/all/0/1">Somenath Chakrabarty</a>HST Imaging of Fading AGN Candidates I: Host-Galaxy Properties and Origin of the Extended Gas. (arXiv:1408.5159v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1408.5159
<p>We present narrow- and medium-band HST imaging, with additional supporting
ground-based data, for 8 galaxies identified as hosting fading AGN. These have
AGN-ionized gas projected &gt;10 kpc from the nucleus, and significant shortfall
of ionizing radiation between the distant gas and the AGN, indicating fading
AGN on ~50,000-year timescales. Every system shows evidence of ongoing or past
interactions; a similar sample of obscured AGN with extended ionized clouds
shares this incidence of disturbances. Several systems show multiple dust lanes
in different orientations, broadly fit by differentially precessing disks of
accreted material ~1.5 Gyr after initial arrival. The gas has lower metallicity
than the nuclei; three systems have abundances uniformly well below solar,
consistent with an origin in tidally disrupted low-luminosity galaxies, while
some systems have more nearly solar abundances (accompanied by such signatures
as multiple Doppler components), which may suggest redistribution of gas by
outflows within the host galaxies themselves. These aspects are consistent with
a tidal origin for the extended gas in most systems, although the ionized gas
and stellar tidal features do not always match closely. In contrast to clouds
near radio-loud AGN, these are dominated by rotation, in some cases in warped
disks. Outflows are important only in localized regions near some of the AGN.
In UGC 7342 and UGC 11185, luminous star clusters are seen within projected
ionization cones, potentially triggered by outflows. As in the discovery
example Hanny's Voorwerp/IC 2497, some clouds lack a strong correlation between
H-alpha surface brightness and ionization parameter, indicating unresolved fine
structure. Together with thin coherent filaments spanning several kpc,
persistence of these structures over their orbital lifetimes may require a role
for magnetic confinement. (Abridged)
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Keel_W/0/1/0/all/0/1">William C. Keel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maksym_W/0/1/0/all/0/1">W. Peter Maksym</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bennert_V/0/1/0/all/0/1">Vardha N. Bennert</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lintott_C/0/1/0/all/0/1">Chris J. Lintott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chojnowski_S/0/1/0/all/0/1">S. Drew Chojnowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moiseev_A/0/1/0/all/0/1">Alexei Moiseev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smirnova_A/0/1/0/all/0/1">Aleksandrina Smirnova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schawinski_K/0/1/0/all/0/1">Kevin Schawinski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Urry_C/0/1/0/all/0/1">C. Megan Urry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evans_D/0/1/0/all/0/1">Daniel A. Evans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pancoast_A/0/1/0/all/0/1">Anna Pancoast</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scott_B/0/1/0/all/0/1">Bryan Scott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Showley_C/0/1/0/all/0/1">Charles Showley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Flatland_K/0/1/0/all/0/1">Kelsi Flatland</a>Is scalar-tensor gravity consistent with polytropic stellar models?. (arXiv:1408.6035v2 [gr-qc] UPDATED)http://arxiv.org/abs/1408.6035
<p>We study the scalar field potential $V(\phi)$ in the scalar-tensor gravity
with self-consistent polytropic stellar configurations. Without choosing a
particular potential, we numerically derive the potential inside various
stellar objects. We restrict the potential to conform to general relativity or
to $f(R)$ gravity inside and require the solution to arrive at SdS vacuum at
the surface. The studied objects are required to obtain observationally valid
masses and radii corresponding to solar type stars, white dwarfs and neutron
stars. We find that the resulting scalar-tensor potential $V(\phi)$ for the
numerically derived polytrope that conforms to general relativity, in each
object class, is highly dependent on the matter configuration as well as on the
vacuum requirement at the boundary. As a result, every stellar configuration
arrives at a potential $V(\phi)$ that is not consistent with the other stellar
class potentials. Therefore, a general potential that conforms to all these
polytropic stellar classes could not be found.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Henttunen_K/0/1/0/all/0/1">Kaisa Henttunen</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Vilja_I/0/1/0/all/0/1">Iiro Vilja</a>The effect of non-Gaussianity on error predictions for the Epoch of Reionization (EoR) 21-cm power spectrum. (arXiv:1409.4420v4 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1409.4420
<p>The Epoch of Reionization (EoR) 21-cm signal is expected to become
increasingly non-Gaussian as reionization proceeds. We have used semi-numerical
simulations to study how this affects the error predictions for the EoR 21-cm
power spectrum. We expect $SNR=\sqrt{N_k}$ for a Gaussian random field where
$N_k$ is the number of Fourier modes in each $k$ bin. We find that
non-Gaussianity is important at high $SNR$ where it imposes an upper limit
$[SNR]_l$. For a fixed volume $V$, it is not possible to achieve $SNR &gt;
[SNR]_l$ even if $N_k$ is increased. The value of $[SNR]_l$ falls as
reionization proceeds, dropping from $\sim 500$ at $\bar{x}_{HI} = 0.8-0.9$ to
$\sim 10$ at $\bar{x}_{HI} = 0.15 $ for a $[150.08\, {\rm Mpc}]^3$ simulation.
We show that it is possible to interpret $[SNR]_l$ in terms of the trispectrum,
and we expect $[SNR]_l \propto \sqrt{V}$ if the volume is increased. For $SNR
\ll [SNR]_l$ we find $SNR = \sqrt{N_k}/A $ with $A \sim 0.95 - 1.75$, roughly
consistent with the Gaussian prediction. We present a fitting formula for the
$SNR$ as a function of $N_k$, with two parameters $A$ and $[SNR]_l$ that have
to be determined using simulations. Our results are relevant for predicting the
sensitivity of different instruments to measure the EoR 21-cm power spectrum,
which till date have been largely based on the Gaussian assumption.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Mondal_R/0/1/0/all/0/1">Rajesh Mondal</a> (IIT Kharagpur), <a href="http://arxiv.org/find/astro-ph/1/au:+Bharadwaj_S/0/1/0/all/0/1">Somnath Bharadwaj</a> (IIT Kharagpur), <a href="http://arxiv.org/find/astro-ph/1/au:+Majumdar_S/0/1/0/all/0/1">Suman Majumdar</a> (Stockholm U), <a href="http://arxiv.org/find/astro-ph/1/au:+Bera_A/0/1/0/all/0/1">Apurba Bera</a> (IIT Kharagpur), <a href="http://arxiv.org/find/astro-ph/1/au:+Acharyya_A/0/1/0/all/0/1">Ayan Acharyya</a> (IIT Kharagpur)Non-Radial Instabilities and Progenitor Asphericities in Core-Collapse Supernovae. (arXiv:1409.4783v2 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1409.4783
<p>Since core-collapse supernova simulations still struggle to produce robust
neutrino-driven explosions in 3D, it has been proposed that asphericities
caused by convection in the progenitor might facilitate shock revival by
boosting the activity of non-radial hydrodynamic instabilities in the
post-shock region. We investigate this scenario in depth using 42 relativistic
2D simulations with multi-group neutrino transport to examine the effects of
velocity and density perturbations in the progenitor for different perturbation
geometries that obey fundamental physical constraints (like the anelastic
condition). As a framework for analysing our results, we introduce
semi-empirical scaling laws relating neutrino heating, average turbulent
velocities in the gain region, and the shock deformation in the saturation
limit of non-radial instabilities. The squared turbulent Mach number, &lt;Ma^2&gt;,
reflects the violence of aspherical motions in the gain layer, and explosive
runaway occurs for &lt;Ma^2&gt;~0.3, corresponding to a reduction of the critical
neutrino luminosity by ~25% compared to 1D. In the light of this theory,
progenitor asphericities aid shock revival mainly by creating anisotropic mass
flux onto the shock: Differential infall efficiently converts velocity
perturbations in the progenitor into density perturbations (Delta rho/rho) at
the shock of the order of the initial convective Mach number Ma. The
anisotropic mass flux and ram pressure deform the shock and thereby amplify
post-shock turbulence. Large-scale (l=2,l=1) modes prove most conducive to
shock revival, whereas small-scale perturbations require unrealistically high
convective Mach numbers. Initial density perturbations in the progenitor are
only of order Ma^2 and therefore play a subdominant role.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Muller_B/0/1/0/all/0/1">B. M&#xfc;ller</a> (Monash University), <a href="http://arxiv.org/find/astro-ph/1/au:+Janka_H/0/1/0/all/0/1">H.-Th. Janka</a> (Max Planck Institute for Astrophysics)A short note on the curvature perturbation at second order. (arXiv:1409.5106v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1409.5106
<p>Working with perturbations about an FLRW spacetime, we compute the
gauge-invariant curvature perturbation to second order solely in terms of
scalar field fluctuations. Using the curvature perturbation on uniform density
hypersurfaces as our starting point, we give our results in terms of field
fluctuations in the flat gauge, incorporating both large and small scale
behaviour. For ease of future numerical implementation we give our result in
terms of the scalar field fluctuations and their time derivatives.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Christopherson_A/0/1/0/all/0/1">Adam J. Christopherson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nalson_E/0/1/0/all/0/1">Ellie Nalson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Malik_K/0/1/0/all/0/1">Karim A. Malik</a>Analyzing the Data from X-ray Polarimeters with Stokes Parameters. (arXiv:1409.6214v2 [astro-ph.IM] UPDATED)http://arxiv.org/abs/1409.6214
<p>X-ray polarimetry promises to deliver unique information about the geometry
of the inner accretion flow of astrophysical black holes and the nature of
matter and electromagnetism in and around neutron stars. In this paper, we
discuss the possibility to use Stokes parameters - a commonly used tool in
radio, infrared, and optical polarimetry - to analyze the data from X-ray
polarimeters such as scattering polarimeters and photoelectric effect
polarimeters, which measure the linear polarization of the detected X-rays.
Based on the azimuthal scattering angle (in the case of a scattering
polarimeter) or the azimuthal component of the angle of the electron ejection
(in the case of a photoelectric effect polarimeter), the Stokes parameters can
be calculated for each event recorded in the detector. Owing to the additive
nature of Stokes parameters, the analysis reduces to adding the Stokes
parameters of the individual events and subtracting the Stokes parameters
characterizing the background (if present). The main strength of this kind of
analysis is that the errors on the Stokes parameters can be computed easily and
are well behaved - in stark contrast of the errors on the polarization fraction
and polarization direction. We demonstrate the power of the Stokes analysis by
deriving several useful formulae, e.g. the expected error on the polarization
fraction and polarization direction for a detection of $N_S$ signal and
$N_{BG}$ background events, the optimal observation times of the signal and
background regions in the presence of non-negligible background contamination
of the signal, and the minimum detectable polarization (MDP) that can be
achieved when following this prescription.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Kislat_F/0/1/0/all/0/1">F. Kislat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_B/0/1/0/all/0/1">B. Clark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beilicke_M/0/1/0/all/0/1">M. Beilicke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krawczynski_H/0/1/0/all/0/1">H. Krawczynski</a>Multiple Lensing of the Cosmic Microwave Background anisotropies. (arXiv:1409.7680v4 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1409.7680
<p>We study the gravitational lensing effect on the Cosmic Microwave Background
(CMB) anisotropies performing a ray-tracing of the primordial CMB photons
through intervening large-scale structures (LSS) distribution predicted by
N-Body numerical simulations with a particular focus on the precise recovery of
the lens-induced polarized counterpart of the source plane. We apply both a
multiple plane ray-tracing and an effective deflection approach based on the
Born approximation to deflect the CMB photons trajectories through the
simulated lightcone. We discuss the results obtained with both these methods
together with the impact of LSS non-linear evolution on the CMB temperature and
polarization power spectra. We compare our results with semi-analytical
approximations implemented in Boltzmann codes like, e.g., CAMB. We show that,
with our current N-body setup, the predicted lensing power is recovered with
good accuracy in a wide range of multipoles while excess power with respect to
semi-analytic prescriptions is observed in the lensing potential on scales
$\ell \gtrsim 3000$. We quantify the impact of the numerical effects connected
to the resolution in the N-Body simulation together with the resolution and
band-limit chosen to synthesise the CMB source plane. We found these quantities
to be particularly important for the simulation of B-mode polarization power
spectrum.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Calabrese_M/0/1/0/all/0/1">Matteo Calabrese</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carbone_C/0/1/0/all/0/1">Carmelita Carbone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fabbian_G/0/1/0/all/0/1">Giulio Fabbian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baldi_M/0/1/0/all/0/1">Marco Baldi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baccigalupi_C/0/1/0/all/0/1">Carlo Baccigalupi</a>The effective theory of fluids at NLO and implications for dark energy. (arXiv:1410.2793v2 [hep-th] UPDATED)http://arxiv.org/abs/1410.2793
<p>We present the effective theory of fluids at next-to-leading order in
derivatives, including an operator that has not been considered until now. The
power-counting scheme and its connection with the propagation of phonon and
metric fluctuations are emphasized. In a perturbed FLRW geometry the theory
presents a set of features that make it very rich for modelling the
acceleration of the Universe. These include anisotropic stress, a non-adiabatic
speed of sound and modifications to the standard equations of vector and tensor
modes. These effects are determined by an energy scale which controls the size
of the high derivative terms and ensures that no instabilities appear.
</p>
<a href="http://arxiv.org/find/hep-th/1/au:+Ballesteros_G/0/1/0/all/0/1">Guillermo Ballesteros</a>The Radiative Efficiency of a Radiatively Inefficient Accretion Flow. (arXiv:1410.3760v2 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1410.3760
<p>A recent simultaneous XMM-Newton/NuSTAR observation of the accreting neutron
star Cen X-4 (L ~ 1.5e33 erg/s) revealed a hard power-law component (\Gamma\ ~
1-1.5) with a relatively low cut-off energy (~10 keV), suggesting
bremsstrahlung emission. The physical requirements for bremsstrahlung combined
with other observed properties of Cen X-4 suggest the emission comes from a
boundary layer rather than in the accretion flow. The accretion flow itself is
thus undetected (with an upper limit of L(flow) &lt; 0.3 L(total)). A deep search
for coherent pulsations (which would indicate a strong magnetic field) places a
6% upper limit on the fractional amplitude of pulsations, suggesting the flow
is not magnetically regulated. Considering the expected energetic balance
between the accretion flow and the boundary layer for different values of the
neutron star parameters (size, magnetic field, and spin) we use the observation
to put a measured upper limit on L(flow), and thus set an upper limit of
\epsilon\ &lt; 0.3 for the intrinsic radiative efficiency of the accretion flow
for the most likely model of a fast-spinning, non-magnetic neutron star. The
non-detection of the accretion flow provides the first direct evidence that
this flow is indeed `radiatively inefficient', i.e. most of the gravitational
potential energy lost by the flow before it hits the star is not emitted as
radiation.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+DAngelo_C/0/1/0/all/0/1">C. R. D&#x27;Angelo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fridriksson_J/0/1/0/all/0/1">J. K. Fridriksson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Messenger_C/0/1/0/all/0/1">C. Messenger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Patruno_A/0/1/0/all/0/1">A. Patruno</a>Evidence of cross-correlation between the CMB lensing and the gamma-ray sky. (arXiv:1410.4997v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1410.4997
<p>We report the measurement of the angular power spectrum of cross-correlation
between the unresolved component of the Fermi-LAT gamma-ray sky-maps and the
CMB lensing potential map reconstructed by the Planck satellite. The matter
distribution in the Universe determines the bending of light coming from the
last scattering surface. At the same time, the matter density drives the growth
history of astrophysical objects, including their capability at generating
non-thermal phenomena, which in turn give rise to gamma-ray emissions. The
Planck lensing map provides information on the integrated distribution of
matter, while the integrated history of gamma-ray emitters is imprinted in the
Fermi-LAT sky maps. We report here the first evidence of their correlation. We
find that the multipole dependence of the cross-correlation measurement is in
agreement with current models of the gamma-ray luminosity function for AGN and
star forming galaxies, with a statistical evidence of 3.0$\sigma$. Moreover,
its amplitude can in general be matched only assuming that these extra-galactic
emitters are also the bulk contribution of the measured isotopic gamma-ray
background (IGRB) intensity. This leaves little room for a big contribution
from galactic sources to the IGRB measured by Fermi-LAT, pointing toward a
direct evidence of the extragalactic origin of the IGRB.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Fornengo_N/0/1/0/all/0/1">N. Fornengo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perotto_L/0/1/0/all/0/1">L. Perotto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Regis_M/0/1/0/all/0/1">M. Regis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Camera_S/0/1/0/all/0/1">S. Camera</a>Signal inference with unknown response: Calibration-uncertainty renormalized estimator. (arXiv:1410.6289v2 [physics.data-an] UPDATED)http://arxiv.org/abs/1410.6289
<p>The calibration of a measurement device is crucial for every scientific
experiment, where a signal has to be inferred from data. We present CURE, the
calibration uncertainty renormalized estimator, to reconstruct a signal and
simultaneously the instrument's calibration from the same data without knowing
the exact calibration, but its covariance structure. The idea of CURE,
developed in the framework of information field theory, is starting with an
assumed calibration to successively include more and more portions of
calibration uncertainty into the signal inference equations and to absorb the
resulting corrections into renormalized signal (and calibration) solutions.
Thereby, the signal inference and calibration problem turns into solving a
single system of ordinary differential equations and can be identified with
common resummation techniques used in field theories. We verify CURE by
applying it to a simplistic toy example and compare it against existent
self-calibration schemes, Wiener filter solutions, and Markov Chain Monte Carlo
sampling. We conclude that the method is able to keep up in accuracy with the
best self-calibration methods and serves as a non-iterative alternative to it.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Dorn_S/0/1/0/all/0/1">Sebastian Dorn</a>, <a href="http://arxiv.org/find/physics/1/au:+Ensslin_T/0/1/0/all/0/1">Torsten A. En&#xdf;lin</a>, <a href="http://arxiv.org/find/physics/1/au:+Greiner_M/0/1/0/all/0/1">Maksim Greiner</a>, <a href="http://arxiv.org/find/physics/1/au:+Selig_M/0/1/0/all/0/1">Marco Selig</a>, <a href="http://arxiv.org/find/physics/1/au:+Boehm_V/0/1/0/all/0/1">Vanessa Boehm</a>Magnetic field instability in a neutron star driven by the electroweak electron-nucleon interaction versus the chiral magnetic effect. (arXiv:1410.6676v2 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1410.6676
<p>We show that the Standard Model electroweak interaction of ultrarelativistic
electrons with nucleons ($eN$ interaction) in a neutron star (NS) permeated by
a seed large-scale helical magnetic field provides its growth up to $\gtrsim
10^{15}\thinspace\text{G}$ during a time comparable with the ages of young
magnetars $\sim 10^4\thinspace\text{yr}$. The magnetic field instability
originates from the parity violation in the $eN$ interaction entering the
generalized Dirac equation for right and left massless electrons in an external
uniform magnetic field. We calculate the averaged electric current given by the
solution of the modified Dirac equation containing an extra current for right
and left electrons (positrons), which turns out to be directed along the
magnetic field. Such current includes both a changing chiral imbalance of
electrons and the $eN$ potential given by a constant neutron density in NS.
Then we derive the system of the kinetic equations for the chiral imbalance and
the magnetic helicity which accounts for the $eN$ interaction. By solving this
system, we show that a sizable chiral imbalance arising in a neutron protostar
due to the Urca-process $e^-_\mathrm{L} + p\to N + \nu_\mathrm{eL}$ diminishes
very rapidly because of a huge chirality flip rate. Thus the $eN$ term prevails
the chiral effect providing a huge growth of the magnetic helicity and the
helical magnetic field.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Dvornikov_M/0/1/0/all/0/1">Maxim Dvornikov</a> (1, 2, 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Semikoz_V/0/1/0/all/0/1">Victor B. Semikoz</a> (2) ((1) University of S&#xe3;o Paulo, (2) IZMIRAN, (3) Tomsk State University)Exploring stellar evolution models of sdB stars using MESA. (arXiv:1410.8204v3 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1410.8204
<p>Stellar evolution calculations have had great success reproducing the
observed atmospheric properties of different classes of stars. Recent
detections of g-mode pulsations in evolved He burning stars allow a rare
comparison of their internal structure with stellar models. Asteroseismology of
subdwarf B stars suggests convective cores of $0.22-0.28\,M_\odot$, $\gtrsim
45\,\%$ of the total stellar mass. Previous studies found significantly smaller
convective core masses ($\lesssim 0.19\,M_\odot$) at a comparable evolutionary
stage.
</p>
<p>We evolved stellar models with MESA (Modules for Experiments in Stellar
Astrophysics) to explore how well the interior structure inferred from
asteroseismology can be reproduced by standard algorithms. Our qualitative
evolutionary paths, position in the $\log g-T_{\rm{eff}}$ diagram and model
timescales are consistent with previous results. SdB masses from our full
evolutionary sequences fall within the range of the empirical sdB mass
distribution, but are nearly always lower than the median.
</p>
<p>Using standard MLT with atomic diffusion we find convective core masses of
$\sim 0.17-0.18 M_\odot$, averaged over the entire sdB lifetime. We can
increase the convective core sizes to be as large as those inferred from
asteroseismology, but only for extreme values of the overshoot parameter
(overshoot gives numerically unstable and physically unrealistic behavior at
the boundary). High resolution three-dimensional (3D) simulations of turbulent
convection in stars suggest that the Schwarzschild criterion for convective
mixing sytematically {\it underestimates the actual extent of mixing because a
boundary layer forms.} Accounting for this would decrease the errors in both
sdB total and convective core masses.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Schindler_J/0/1/0/all/0/1">Jan-Torge Schindler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Green_E/0/1/0/all/0/1">Elizabeth M. Green</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arnett_W/0/1/0/all/0/1">W. David Arnett</a>On properties of Velikhov-Chandrasekhar MRI in ideal and non-ideal plasma. (arXiv:1412.1223v2 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1412.1223
<p>Conditions of Velikhov-Chandrasekhar magneto-rotational instability in ideal
and non-ideal plasmas are examined. Linear WKB analysis of hydromagnetic
axially symmetric flows shows that in the Rayleigh-unstable hydrodynamic case
where the angular momentum decreases with radius, the MRI branch becomes
stable, and the magnetic field suppresses the Rayleigh instability at small
wavelengths. We investigate the limiting transition from hydromagnetic flows to
hydrodynamic flows. The Rayleigh mode smoothly transits to the hydrodynamic
case, while the Velikhov-Chandrasekhar MRI mode completely disappears without
the magnetic field. The effects of viscosity and magnetic diffusivity in plasma
on the MRI conditions in thin accretion discs are studied. We find the limits
on the mean free-path of ions allowing MRI to operate in such discs.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Shakura_N/0/1/0/all/0/1">N.I. Shakura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Postnov_K/0/1/0/all/0/1">K.A. Postnov</a> (Sternberg Astronomical Institute, Moscow University, Russia)Ghosts in classes of non-local gravity. (arXiv:1412.1575v2 [gr-qc] UPDATED)http://arxiv.org/abs/1412.1575
<p>We consider a class of non-local gravity theories where the Lagrangian is a
function of powers of the inverse d'Alembertian operator acting on the Ricci
scalar. We take an approach in which the non-local Lagrangian is made local by
introducing auxiliary scalar fields, and study the degrees of freedom of the
localized Lagrangian. We find that among the auxiliary scalar fields
introduced, some of them are always ghost-like. That is, in the Einstein frame
they develop a negative kinetic term. Because of this, except for a particular
case already known in the literature, in general, it is not clear how to
quantize these models and how to interpret this theory in the light of standard
field theory.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Felice_A/0/1/0/all/0/1">Antonio De Felice</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Sasaki_M/0/1/0/all/0/1">Misao Sasaki</a>Neglecting Primordial non-Gaussianity Threatens Future Cosmological Experiment Accuracy. (arXiv:1412.5172v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1412.5172
<p>Future galaxy redshift surveys aim at probing the clustering of the cosmic
large-scale structure with unprecedented accuracy, thus complementing cosmic
microwave background experiments in the quest to deliver the most precise and
accurate picture ever of our Universe. Analyses of such measurements are
usually performed within the context of the so-called vanilla LCDM model - the
six-parameter phenomenological model which, for instance, emerges from best
fits against the recent data obtained by the Planck satellite. Here, we show
that such an approach is prone to subtle systematics when the Gaussianity of
primordial fluctuations is concerned. In particular, we demonstrate that, if we
neglect even a tiny amount of primordial non-Gaussianity - fully consistent
with current limits - we shall introduce spurious biases in the reconstruction
of cosmological parameters. This is a serious issue that must be properly
accounted for in view of accurate (as well as precise) cosmology.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Camera_S/0/1/0/all/0/1">Stefano Camera</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carbone_C/0/1/0/all/0/1">Carmelita Carbone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fedeli_C/0/1/0/all/0/1">Cosimo Fedeli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moscardini_L/0/1/0/all/0/1">Lauro Moscardini</a>New Bayesian analysis of hybrid EoS constraints with mass-radius data for compact stars. (arXiv:1412.8226v2 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1412.8226
<p>We suggest a new Bayesian analysis using disjunct mass and radius constraints
for extracting probability measures for cold, dense nuclear matter equations of
state. One of the key issues of such an analysis is the question of a
deconfinement transition in compact stars and whether it proceeds as a
crossover or rather as a first order transition. The latter question is
relevant for the possible existence of a critical endpoint in the QCD phase
diagram under scrutiny in present and upcoming heavy-ion collision experiments.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Ayriyan_A/0/1/0/all/0/1">A. Ayriyan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alvarez_Castillo_D/0/1/0/all/0/1">D. E. Alvarez-Castillo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blaschke_D/0/1/0/all/0/1">D. Blaschke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grigorian_H/0/1/0/all/0/1">H. Grigorian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sokolowski_M/0/1/0/all/0/1">M. Sokolowski</a>All-sky reconstruction of the primordial scalar potential from WMAP temperature data. (arXiv:1412.8315v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1412.8315
<p>An essential quantity required to understand the physics of the early
Universe, in particular the inflationary epoch, is the primordial scalar
potential $\Phi$ and its statistics. We present for the first time an all-sky
reconstruction of $\Phi$ with corresponding $1\sigma$-uncertainty from WMAP's
cosmic microwave background (CMB) temperature data -- a map of the very early
Universe right after the inflationary epoch. This has been achieved by applying
a Bayesian inference method that separates the whole inverse problem of the
reconstruction into many independent ones, each of them solved by an optimal
linear filter (Wiener filter). In this way, the three-dimensional potential
$\Phi$ gets reconstructed slice by slice resulting in a thick shell of nested
spheres around the comoving distance to the last scattering surface. Each slice
represents the primordial scalar potential $\Phi$ projected onto a sphere with
corresponding distance. Furthermore, we present an advanced method for
inferring $\Phi$ and its power spectrum simultaneously from data, but argue
that applying it requires polarization data with high signal-to-noise levels
not available yet. Future CMB data should improve results significantly, as
polarization data will fill the present $\ell-$blind gaps of the
reconstruction.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Dorn_S/0/1/0/all/0/1">Sebastian Dorn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Greiner_M/0/1/0/all/0/1">Maksim Greiner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ensslin_T/0/1/0/all/0/1">Torsten A. En&#xdf;lin</a>Non-conformal evolution of magnetic fields during reheating. (arXiv:1501.03057v2 [gr-qc] UPDATED)http://arxiv.org/abs/1501.03057
<p>We consider the evolution of electromagnetic fields coupled to conduction
currents during the reheating era after inflation, and prior to the
establishing of the proton-electron plasma. We assume that the currents may be
described by second order causal hydrodynamics. The resulting theory is not
conformally invariant. The expansion of the Universe produces temperature
gradients which couple to the current and generally oppose Ohmic dissipation.
Although the effect is not strong, it suggests that the unfolding of
hydrodynamic instabilities in these models may follow a different pattern than
in first order theories, and even than in second order theories on non
expanding backgrounds.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Calzetta_E/0/1/0/all/0/1">Esteban Calzetta</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Kandus_A/0/1/0/all/0/1">Alejandra Kandus</a>Disformal couplings and the dark sector of the universe. (arXiv:1501.03073v3 [gr-qc] UPDATED)http://arxiv.org/abs/1501.03073
<p>Interactions between dark matter and dark energy, allowing both conformal and
and disformal couplings, are studied in detail. We discuss the background
evolution, anisotropies in the cosmic microwave background and large scale
structures. One of our main findings is that a large conformal coupling is not
necessarily disallowed in the presence of a general disformal term. On the
other hand, we find that negative disformal couplings very often lead to
instabilities in the scalar field. Studying the background evolution and linear
perturbations only, our results show that it is observationally challenging to
disentangle disformal from purely conformal couplings.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Bruck_C/0/1/0/all/0/1">C. van de Bruck</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Morrice_J/0/1/0/all/0/1">J. Morrice</a>Constraining the distribution of dark matter in dwarf spheroidal galaxies with stellar tidal streams. (arXiv:1501.04968v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1501.04968
<p>We use high-resolution N-body simulations to follow the formation and
evolution of tidal streams associated to dwarf spheroidal galaxies (dSphs). The
dSph models are embedded in dark matter (DM) haloes with either a
centrally-divergent 'cusp', or an homogeneous-density 'core'. In agreement with
previous studies, we find that as tides strip the galaxy the evolution of the
half-light radius and the averaged velocity dispersion follows well-defined
tracks that are mainly controlled by the amount of mass lost. Crucially, the
evolutionary tracks behave differently depending on the shape of the DM
profile: at a fixed remnant mass, dSphs embedded in cored haloes have larger
sizes and higher velocity dispersions than their cuspy counterparts. The
divergent evolution is particularly pronounced in galaxies whose stellar
component is strongly segregated within their DM halo and becomes more
disparate as the remnant mass decreases. Our analysis indicates that the DM
profile plays an important role in defining the internal dynamics of tidal
streams. We find that stellar streams associated to cored DM models have
velocity dispersions that lie systematically above their cuspy counterparts.
Our results suggest that the dynamics of streams with known dSph progenitors
may provide strong constraints on the distribution of DM on the smallest
galactic scales.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Errani_R/0/1/0/all/0/1">Rapha&#xeb;l Errani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Penarrubia_J/0/1/0/all/0/1">Jorge Pe&#xf1;arrubia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tormen_G/0/1/0/all/0/1">Giuseppe Tormen</a>SDSS J1138+3517: A quasar showing remarkably variable broad absorption lines. (arXiv:1501.04975v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1501.04975
<p>We report on the highly variable SiIV and CIV broad absorption lines in SDSS
J113831.4+351725.2 across four observational epochs. Using the SiIV doublet
components, we find that the blue component is usually saturated and non-black,
with the ratio of optical depths between the two components rarely being 2:1.
This indicates that these absorbers do not fully cover the line-of-sight and
thus a simple apparent optical depth model is insufficient when measuring the
true opacity of the absorbers. Tests with inhomogeneous (power-law) and
pure-partial coverage (step-function) models of the absorbing SiIV optical
depth predict the most un-blended doublet's component profiles equally well.
However, when testing with Gaussian-fitted doublet components to all SiIV
absorbers and averaging the total absorption predicted in each doublet, the
upper limit of the power law index is mostly unconstrained. This leads us to
favour pure partial coverage as a more accurate measure of the true optical
depth than the inhomogeneous power law model.
</p>
<p>The pure-partial coverage model indicates no significant change in covering
fraction across the epochs, with changes in the incident ionizing flux on the
absorbing gas instead being favoured as the variability mechanism. This is
supported by (a) the coordinated behaviour of the absorption troughs, (b) the
behaviour of the continuum at the blue end of the spectrum and (c) the
consistency of photoionization simulations of ionic column density dependencies
on ionization parameter with the observed variations. Evidence from the
simulations together with the CIV absorption profile indicates that the
absorber lies outside the broad line region, though the precise distance and
kinetic luminosity are not well constrained.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Wildy_C/0/1/0/all/0/1">Conor Wildy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Goad_M/0/1/0/all/0/1">Michael R. Goad</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Allen_J/0/1/0/all/0/1">James T. Allen</a>Nonlinear closures for scale separation in supersonic magnetohydrodynamic turbulence. (arXiv:1501.07170v2 [physics.flu-dyn] UPDATED)http://arxiv.org/abs/1501.07170
<p>Turbulence in compressible plasma plays a key role in many areas of
astrophysics and engineering. The extreme plasma parameters in these
environments, e.g. high Reynolds numbers, supersonic and super-Alfvenic flows,
however, make direct numerical simulations computationally intractable even for
the simplest treatment -- magnetohydrodynamics (MHD). To overcome this problem
one can use subgrid-scale (SGS) closures -- models for the influence of
unresolved, subgrid-scales on the resolved ones. In this work we propose and
validate a set of constant coefficient closures for the resolved, compressible,
ideal MHD equations. The subgrid-scale energies are modeled by Smagorinsky-like
equilibrium closures. The turbulent stresses and the electromotive force (EMF)
are described by expressions that are nonlinear in terms of large scale
velocity and magnetic field gradients. To verify the closures we conduct a
priori tests over 137 simulation snapshots from two different codes with
varying ratios of thermal to magnetic pressure ($\beta_\mathrm{p} = 0.25, 1,
2.5, 5, 25$) and sonic Mach numbers ($M_s = 2, 2.5, 4$). Furthermore, we make a
comparison to traditional, phenomenological eddy-viscosity and
$\alpha-\beta-\gamma$ closures. We find only mediocre performance of the
kinetic eddy-viscosity and $\alpha-\beta-\gamma$ closures, and that the
magnetic eddy-viscosity closure is poorly correlated with the simulation data.
Moreover, three of five coefficients of the traditional closures exhibit a
significant spread in values. In contrast, our new closures demonstrate
consistently high correlation and constant coefficient values over time and and
over the wide range of parameters tested. Important aspects in compressible MHD
turbulence such as the bi-directional energy cascade, turbulent magnetic
pressure and proper alignment of the EMF are well described by our new
closures.
</p>
<a href="http://arxiv.org/find/physics/1/au:+Grete_P/0/1/0/all/0/1">Philipp Grete</a>, <a href="http://arxiv.org/find/physics/1/au:+Vlaykov_D/0/1/0/all/0/1">Dimitar G Vlaykov</a>, <a href="http://arxiv.org/find/physics/1/au:+Schmidt_W/0/1/0/all/0/1">Wolfram Schmidt</a>, <a href="http://arxiv.org/find/physics/1/au:+Schleicher_D/0/1/0/all/0/1">Dominik R G Schleicher</a>, <a href="http://arxiv.org/find/physics/1/au:+Federrath_C/0/1/0/all/0/1">Christoph Federrath</a>Decoupled Sectors and Wolf-Rayet Galaxies. (arXiv:1502.03463v2 [hep-ph] UPDATED)http://arxiv.org/abs/1502.03463
<p>The universe may contain several decoupled matter sectors which primarily
couple through gravity to the Standard Model degrees of freedom. We focus here
on the description of astrophysical environments that allow for comparable
densities and spatial distributions of visible matter and decoupled dark
matter. We discuss four Wolf-Rayet galaxies (NGC 1614, NGC 3367, NGC 4216 and
NGC 5430) which should contain comparable amounts of decoupled dark and visible
matter in the star forming regions. This could lead to the observation of Gamma
Ray Burst events with physics modified by jets of dark matter radiation.
</p>
<a href="http://arxiv.org/find/hep-ph/1/au:+Fischler_W/0/1/0/all/0/1">Willy Fischler</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Lorshbough_J/0/1/0/all/0/1">Jimmy Lorshbough</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Lorshbough_D/0/1/0/all/0/1">Dustin Lorshbough</a>Sub-MeV Band Observation of a Hard Burst from AXP 1E 1547.0-5408 with the Suzaku Wide-band All-sky Monitor. (arXiv:1502.04819v3 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1502.04819
<p>The 2.1-s anomalous X-ray pulsar 1E 1547.0-5408 exhibited an X-ray outburst
on 2009 January 22, emitting a large number of short bursts. The wide-band all-
sky monitor (WAM) on-board Suzaku detected at least 254 bursts in the
160keV-6.2MeV band over the period of January 22 00:57-17:02 UT from the
direction of 1E 1547.0-5408. One of these bursts, which occurred at 06:45:13,
produced the brightest fluence in the 0.5-6.2MeV range, with an averaged
0.16-6.2MeV flux and extrapolated 25 keV-2 MeV fluence of about 3x10-6 erg cm-2
s-1 and about 3x10-4 erg cm-2, respectively. After pile-up corrections, the
time-resolved WAM spectra of this burst were well-fitted in the 0.16-6.2MeV
range by two-component models; specifically, a blackbody plus an optically thin
thermal bremsstrahlung or a combination of a blackbody and a power-law
component with an exponential cutoff. These results are compared with previous
works reporting the persistent emission and weaker short bursts followed by the
same outburst.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Yasuda_T/0/1/0/all/0/1">Tetsuya Yasuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iwakiri_W/0/1/0/all/0/1">Wataru B. Iwakiri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tashiro_M/0/1/0/all/0/1">Makoto S. Tashiro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Terada_Y/0/1/0/all/0/1">Yukikatsu Terada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kouzu_T/0/1/0/all/0/1">Tomomi Kouzu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Enoto_T/0/1/0/all/0/1">Teruaki Enoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakagawa_Y/0/1/0/all/0/1">Yujin E. Nakagawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bamba_A/0/1/0/all/0/1">Aya Bamba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Urata_Y/0/1/0/all/0/1">Yuji Urata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamaoka_K/0/1/0/all/0/1">Kazutaka Yamaoka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohno_M/0/1/0/all/0/1">Masanori Ohno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shibata_S/0/1/0/all/0/1">Sinpei Shibata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Makishima_K/0/1/0/all/0/1">Kazuo Makishima</a>, The <a href="http://arxiv.org/find/astro-ph/1/au:+team_Suzaku_WAM/0/1/0/all/0/1">Suzaku-WAM team</a>Investigating plasma motion of magnetic clouds at 1 AU through a velocity-modified cylindrical force-free flux rope model. (arXiv:1502.05112v2 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1502.05112
<p>Magnetic clouds (MCs) are the interplanetary counterparts of coronal mass
ejections (CMEs), and usually modeled by a flux rope. By assuming the
quasi-steady evolution and self-similar expansion, we introduce three types of
global motion into a cylindrical force-free flux rope model, and developed a
new velocity-modified model for MCs. The three types of the global motion are
the linear propagating motion away from the Sun, the expanding and the poloidal
motion with respect to the axis of the MC. The model is applied to 72 MCs
observed by Wind spacecraft to investigate the properties of the plasma motion
of MCs. First, we find that some MCs had a significant propagation velocity
perpendicular to the radial direction, suggesting the direct evidence of the
CME's deflected propagation and/or rotation in interplanetary space. Second, we
confirm the previous results that the expansion speed is correlated with the
radial propagation speed and most MCs did not expand self-similarly at 1 AU. In
our statistics, about 62\%/17\% of MCs underwent a under/over-expansion at 1 AU
and the expansion rate is about 0.6 on average. Third, most interestingly, we
find that a significant poloidal motion did exist in some MCs. Three
speculations about the cause of the poloidal motion are therefore proposed.
These findings advance our understanding of the MC's properties at 1 AU as well
as the dynamic evolution of CMEs from the Sun to interplanetary space.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Y/0/1/0/all/0/1">Yuming Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_Z/0/1/0/all/0/1">Zhenjun Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shen_C/0/1/0/all/0/1">Chenglong Shen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_R/0/1/0/all/0/1">Rui Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_S/0/1/0/all/0/1">S. Wang</a>Lovelock-Brans-Dicke gravity. (arXiv:1502.05695v2 [gr-qc] UPDATED)http://arxiv.org/abs/1502.05695
<p>According to Lovelock's theorem, the Hilbert-Einstein and the Lovelock
actions are indistinguishable from their field equations. However, they have
different scalar-tensor counterparts, which correspond to the Brans-Dicke and
the \emph{Lovelock-Brans-Dicke} (LBD) gravities, respectively. In this paper
the LBD model of alternative gravity with the Lagrangian density
$\mathscr{L}_{\text{LBD}}=\frac{1}{16\pi}[\phi(R+\frac{a}{\sqrt{-g}}{}^*RR +
b\mathcal{G})-\frac{\omega_{\text L}}{\phi}\nabla_\alpha \phi
\nabla^\alpha\phi]$ is developed, where ${}^*RR$ and $\mathcal{G}$ respectively
denote the topological Chern-Pontryagin and Gauss-Bonnet invariants. The field
equation, the kinematical and dynamical wave equations, and the constraint from
energy-momentum conservation are all derived. It is shown that, the LBD gravity
reduces to general relativity in the limit $\omega_{\text{L}}\to\infty$ unless
the "topological balance condition" holds, and it can be conformally
transformed into the dynamical Chern-Simons gravity in vacuum and for
spacetimes of negligible Gauss-Bonnet effect. Moreover, the LBD gravity allows
for the late-time cosmic acceleration without dark energy. Finally, the LBD
gravity is generalized into the Lovelock-scalar-tensor gravity, and its
equivalence to fourth-order modified gravities is established. It is also
emphasized that the standard expressions for the contributions of generalized
Gauss-Bonnet dependence can be further simplified.
</p>
<a href="http://arxiv.org/find/gr-qc/1/au:+Tian_D/0/1/0/all/0/1">David Wenjie Tian</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Booth_I/0/1/0/all/0/1">Ivan Booth</a>Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence. (arXiv:1502.05801v2 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1502.05801
<p>We developed angular momentum evolution models for 0.5 and 0.8 $M_{\odot}$
stars. The parametric models include a new wind braking law based on recent
numerical simulations of magnetised stellar winds, specific dynamo and
mass-loss rate prescriptions, as well as core/envelope decoupling. We compare
model predictions to the distributions of rotational periods measured for low
mass stars belonging to star forming regions and young open clusters.
Furthermore, we explore the mass dependence of model parameters by comparing
these new models to the solar-mass models we developed earlier. Rotational
evolution models are computed for slow, median, and fast rotators at each
stellar mass. The models reproduce reasonably well the rotational behaviour of
low-mass stars between 1 Myr and 8-10 Gyr, including pre-main sequence to
zero-age main sequence spin up, prompt zero-age main sequence spin down, and
early-main sequence convergence of the surface rotation rates. Fast rotators
are found to have systematically shorter disk lifetimes than moderate and slow
rotators, thus enabling dramatic pre-main sequence spin up. They also have
shorter core-envelope coupling timescales, i.e., more uniform internal
rotation. As to the mass dependence, lower mass stars require significantly
longer core-envelope coupling timescale than solar-type ones, which results in
strong differential rotation developing in the stellar interior on the early
main sequence. Lower mass stars also require a weaker braking torque to account
for their longer spin down timescale on the early main sequence, while they
ultimately converge towards lower rotational velocities than solar-type stars
on the longer term due to their reduced moment of inertia. We also find
evidence that the mass-dependence of the wind braking efficiency may be related
to a change of the magnetic topology in lower mass stars.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Gallet_F/0/1/0/all/0/1">Florian Gallet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouvier_J/0/1/0/all/0/1">J&#xe9;r&#xf4;me Bouvier</a>Chameleon-like cosmology in light of SNeIa, CMB, BAO and OHD observational data sets. (arXiv:1502.05952v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1502.05952
<p>During this work an interacting chameleon-like scalar field scenario, by
considering SNeIa, CMB, BAO and OHD data sets is investigated. Some
cosmological parameters includes of Hubble, deceleration and coincidence
parameters in such mechanism are analysed. It is realized for estimation the
free parameters of a theoretical model, it is better all mentioned
observational data sets be considered. In fact if one considers SNeIa, CMB and
BAO but ignores OHD it maybe leads to an incorrect result. Also it will find
out, when we margin the free parameters, the $\chi_{\rm{T}}^2$ function should
be re-weighted, this fact arises from the abundance of SNeIa and OHD sources in
comparison to CMB and BAO data sets. We margin the likelihood $\mathcal{L}
(\Omega_{\rm{m0}},\omega_1, \beta)$ with respect to $\omega_1$, $\beta$ and
$\Omega_{\rm{m0}}$ respectively and by means of two dimensional confidence
levels $68.3\%$, $90\%$ and $95.4\%$, the relative probability functions are
plotted. Also the quantities which maximize the marginalized likelihoods using
mentioned confidence levels are obtained. In addition, $\chi_{\rm{T}}^2 =
\chi_{{\rm{SNe}}}^2 + \chi_{{\rm{OHD}}}^2 + 3 \, \chi_{{\rm{CMB}}}^2 + 3 \,
\chi_{{\rm{BAO}}}^2$, we margin the relative likelihood functions in one
dimension, and based on these calculations the best fitted free parameters of
the model will be obtained.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Rabiei_S/0/1/0/all/0/1">Sayed Wrya Rabiei</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sheikhahmadi_H/0/1/0/all/0/1">Haidar Sheikhahmadi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saaidi_K/0/1/0/all/0/1">Khaled Saaidi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aghamohammadi_A/0/1/0/all/0/1">Ali Aghamohammadi</a>Gauge-preheating and the end of axion inflation. (arXiv:1502.06506v2 [astro-ph.CO] UPDATED)http://arxiv.org/abs/1502.06506
<p>We study the onset of the reheating epoch at the end of axion-driven
inflation where the axion is coupled to an Abelian, $U(1)$, gauge field via a
Chern-Simons interaction term. We focus primarily on $m^2\phi^2$ inflation and
explore the possibility that preheating can occur for a range of coupling
values consistent with recent observations and bounds on the overproduction of
primordial black holes. We find that for a wide range of parameters preheating
is efficient. In certain cases the inflaton is seen to transfer all its energy
to the gauge fields within a few oscillations. In most cases, we find that the
gauge fields on sub-horizon scales end preheating in an unpolarized state due
to the existence of strong rescattering between the inflaton and gauge-field
modes. We also present a preliminary study of an axion monodromy model coupled
to $U(1)$ gauge fields, seeing a similarly efficient preheating behavior as
well as indications that the coupling strength has an effect on the creation of
oscillons.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Adshead_P/0/1/0/all/0/1">Peter Adshead</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giblin_J/0/1/0/all/0/1">John T. Giblin Jr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scully_T/0/1/0/all/0/1">Timothy R. Scully</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sfakianakis_E/0/1/0/all/0/1">Evangelos I. Sfakianakis</a>Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined Data. (arXiv:1502.06663v2 [astro-ph.EP] UPDATED)http://arxiv.org/abs/1502.06663
<p>We reanalyze microlensing events in the published list of anomalous events
that were observed from the OGLE lensing survey conducted during 2004-2008
period. In order to check the existence of possible degenerate solutions and
extract extra information, we conduct analyses based on combined data from
other survey and follow-up observation and consider higher-order effects. Among
the analyzed events, we present analyses of 8 events for which either new
solutions are identified or additional information is obtained. We find that
the previous binary-source interpretations of 5 events are better interpreted
by binary-lens models. These events include OGLE-2006-BLG-238,
OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210.
With additional data covering caustic crossings, we detect finite-source
effects for 6 events including OGLE-2006-BLG-215, OGLE-2006-BLG-238,
OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513.
Among them, we are able to measure the Einstein radii of 3 events for which
multi-band data are available. These events are OGLE-2006-BLG-238,
OGLE-2008-BLG-210, and OGLE-2008-BLG-513. For OGLE-2008-BLG-143, we detect
higher-order effect induced by the changes of the observer's position caused by
the orbital motion of the Earth around the Sun. In addition, we present
degenerate solutions resulting from the known close/wide or ecliptic
degeneracy. Finally, we note that the masses of the binary companions of the
lenses of OGLE-2006-BLG-450 and OGLE-2008-BLG-210 are in the brown-dwarf
regime.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Jeong_J/0/1/0/all/0/1">J. Jeong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Park_H/0/1/0/all/0/1">H. Park</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Han_C/0/1/0/all/0/1">C. Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gould_A/0/1/0/all/0/1">A. Gould</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Udalski_A/0/1/0/all/0/1">A. Udalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Szymanski_M/0/1/0/all/0/1">M. K. Szyma&#x144;ski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pietrzynski_G/0/1/0/all/0/1">G. Pietrzy&#x144;ski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Soszynski_I/0/1/0/all/0/1">I. Soszy&#x144;ski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poleski_R/0/1/0/all/0/1">R. Poleski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ulaczyk_K/0/1/0/all/0/1">K. Ulaczyk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wyrzykowski_%5C/0/1/0/all/0/1">&#x141;. Wyrzykowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abe_F/0/1/0/all/0/1">F. Abe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bennett_D/0/1/0/all/0/1">D. P. Bennett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bond_I/0/1/0/all/0/1">I. A. Bond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Botzler_C/0/1/0/all/0/1">C. S. Botzler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Freeman_M/0/1/0/all/0/1">M. Freeman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukui_A/0/1/0/all/0/1">A. Fukui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukunaga_D/0/1/0/all/0/1">D. Fukunaga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Itow_Y/0/1/0/all/0/1">Y. Itow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koshimoto_N/0/1/0/all/0/1">N. Koshimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Masuda_K/0/1/0/all/0/1">K. Masuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsubara_Y/0/1/0/all/0/1">Y. Matsubara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Muraki_Y/0/1/0/all/0/1">Y. Muraki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Namba_S/0/1/0/all/0/1">S. Namba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohnishi_K/0/1/0/all/0/1">K. Ohnishi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rattenbury_N/0/1/0/all/0/1">N. J. Rattenbury</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saito_T/0/1/0/all/0/1">To. Saito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sullivan_D/0/1/0/all/0/1">D. J. Sullivan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sweatman_W/0/1/0/all/0/1">W. L. Sweatman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sumi_T/0/1/0/all/0/1">T. Sumi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suzuki_D/0/1/0/all/0/1">D. Suzuki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tristram_P/0/1/0/all/0/1">P. J. Tristram</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsurumi_N/0/1/0/all/0/1">N. Tsurumi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wada_K/0/1/0/all/0/1">K. Wada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamai_N/0/1/0/all/0/1">N. Yamai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yock_P/0/1/0/all/0/1">P. C. M. Yock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yonehara_A/0/1/0/all/0/1">A. Yonehara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrow_M/0/1/0/all/0/1">M. D. Albrow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Batista_V/0/1/0/all/0/1">V. Batista</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beaulieu_J/0/1/0/all/0/1">J.-P. Beaulieu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caldwell_J/0/1/0/all/0/1">J. A. R. Caldwell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cassan_A/0/1/0/all/0/1">A. Cassan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cole_A/0/1/0/all/0/1">A. Cole</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coutures_C/0/1/0/all/0/1">C. Coutures</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dieters_S/0/1/0/all/0/1">S. Dieters</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dominik_M/0/1/0/all/0/1">M. Dominik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prester_D/0/1/0/all/0/1">D. Dominis Prester</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Donatowicz_J/0/1/0/all/0/1">J. Donatowicz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fouque_P/0/1/0/all/0/1">P. Fouqu&#xe9;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Greenhill_J/0/1/0/all/0/1">J. Greenhill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hoffman_M/0/1/0/all/0/1">M. Hoffman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huber_M/0/1/0/all/0/1">M. Huber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jorgensen_U/0/1/0/all/0/1">U. G. J&#xf8;rgensen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kane_S/0/1/0/all/0/1">S. R. Kane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kubas_D/0/1/0/all/0/1">D. Kubas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martin_R/0/1/0/all/0/1">R. Martin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marquette_J/0/1/0/all/0/1">J.-B. Marquette</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Menzies_J/0/1/0/all/0/1">J. Menzies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pitrou_C/0/1/0/all/0/1">C. Pitrou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pollard_K/0/1/0/all/0/1">K. Pollard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sahu_K/0/1/0/all/0/1">K. C. Sahu</a>, et al. (37 additional authors not shown)An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30. (arXiv:1502.07418v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1502.07418
<p>So far, roughly 40 quasars with redshifts greater than z=6 have been
discovered. Each quasar contains a black hole with a mass of about one billion
solar masses ($10^9 M_\odot$). The existence of such black holes when the
Universe was less than 1 billion years old presents substantial challenges to
theories of the formation and growth of black holes and the coevolution of
black holes and galaxies. Here we report the discovery of an ultra-luminous
quasar, SDSS J010013.02+280225.8, at redshift z=6.30. It has an optical and
near-infrared luminosity a few times greater than those of previously known z&gt;6
quasars. On the basis of the deep absorption trough on the blue side of the Ly
$\alpha$ emission line in the spectrum, we estimate the proper size of the
ionized proximity zone associated with the quasar to be 26 million light years,
larger than found with other z&gt;6.1 quasars with lower luminosities. We estimate
(on the basis of a near-infrared spectrum) that the black hole has a mass of
$\sim 1.2 \times 10^{10} M_\odot$, which is consistent with the $1.3 \times
10^{10} M_\odot$ derived by assuming an Eddington-limited accretion rate.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Wu_X/0/1/0/all/0/1">Xue-Bing Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_F/0/1/0/all/0/1">Feige Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fan_X/0/1/0/all/0/1">Xiaohui Fan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yi_W/0/1/0/all/0/1">Weimin Yi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zuo_W/0/1/0/all/0/1">Wenwen Zuo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bian_F/0/1/0/all/0/1">Fuyan Bian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_L/0/1/0/all/0/1">Linhua Jiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McGreer_I/0/1/0/all/0/1">Ian D. McGreer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_R/0/1/0/all/0/1">Ran Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_J/0/1/0/all/0/1">Jinyi Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_Q/0/1/0/all/0/1">Qian Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thompson_D/0/1/0/all/0/1">David Thompson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beletsky_Y/0/1/0/all/0/1">Yuri Beletsky</a>CSI 2264: Probing the inner disks of AA Tau-like systems in NGC 2264. (arXiv:1502.07692v2 [astro-ph.SR] UPDATED)http://arxiv.org/abs/1502.07692
<p>The classical T Tauri star AA Tau presented photometric variability
attributed to an inner disk warp, caused by the interaction between the inner
disk and an inclined magnetosphere. Previous studies of NGC 2264 have shown
that similar photometric behavior is common among CTTS.
</p>
<p>The goal of this work is to investigate the main causes of the observed
photometric variability of CTTS in NGC 2264 that present AA Tau-like light
curves, and verify if an inner disk warp could be responsible for their
variability. We investigate veiling variability in their spectra and u-r color
variations and estimate parameters of the inner disk warp using an occultation
model proposed for AA Tau. We compare infrared and optical light curves to
analyze the dust responsible for the occultations. AA Tau-like variability is
transient on a timescale of a few years. We ascribe it to stable accretion
regimes and aperiodic variability to unstable accretion regimes and show that a
transition, and even coexistence, between the two is common. We find evidence
of hot spots associated with occultations, indicating that the occulting
structures could be located at the base of accretion columns. We find average
values of warp maximum height of 0.23 times its radial location, consistent
with AA Tau, with variations of on average 11% between rotation cycles. We show
that extinction laws in the inner disk indicate the presence of grains larger
than interstellar grains.
</p>
<p>The inner disk warp scenario is consistent with observations for all but one
periodic star in our sample. AA Tau-like systems comprise 14% of CTTS observed
in NGC 2264, though this increases to 35% among systems of mass
0.7M_sun&lt;M&lt;2.0M_sun. Assuming random inclinations, we estimate that nearly all
systems in this mass range likely possess an inner disk warp, possibly because
of a change in magnetic field configurations among stars of lower mass.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+McGinnis_P/0/1/0/all/0/1">Pauline T. McGinnis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alencar_S/0/1/0/all/0/1">Silvia H. P. Alencar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guimaraes_M/0/1/0/all/0/1">Marcelo M. Guimaraes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sousa_A/0/1/0/all/0/1">Alana P. Sousa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stauffer_J/0/1/0/all/0/1">John Stauffer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouvier_J/0/1/0/all/0/1">Jerome Bouvier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rebull_L/0/1/0/all/0/1">Luisa Rebull</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fonseca_N/0/1/0/all/0/1">Nathalia N. J. Fonseca</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Venuti_L/0/1/0/all/0/1">Laura Venuti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hillenbrand_L/0/1/0/all/0/1">Lynne Hillenbrand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cody_A/0/1/0/all/0/1">Ann Marie Cody</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teixeira_P/0/1/0/all/0/1">Paula S. Teixeira</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aigrain_S/0/1/0/all/0/1">Suzanne Aigrain</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Favata_F/0/1/0/all/0/1">Fabio Favata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Furesz_G/0/1/0/all/0/1">Gabor Furesz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vrba_F/0/1/0/all/0/1">Frederick J. Vrba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Flaccomio_E/0/1/0/all/0/1">Ettore Flaccomio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Turner_N/0/1/0/all/0/1">Neal J. Turner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gameiro_J/0/1/0/all/0/1">Jorge Filipe Gameiro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dougados_C/0/1/0/all/0/1">Catherine Dougados</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Herbst_W/0/1/0/all/0/1">William Herbst</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morales_Calderon_M/0/1/0/all/0/1">Maria Morales-Calderon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Micela_G/0/1/0/all/0/1">Giusi Micela</a>The "Green Bean" Galaxy SDSS J224024.1--092748: Unravelling the emission signature of a quasar ionization echo. (arXiv:1502.07754v2 [astro-ph.GA] UPDATED)http://arxiv.org/abs/1502.07754
<p>"Green Bean" Galaxies (GBs) are the most [O III]-luminous type-2 active
galactic nuclei (AGN) at z~0.3. However, their infrared luminosities reveal AGN
in very low activity states, indicating that their gas reservoirs must be
ionized by photons from a recent high activity episode - we are observing
quasar ionization echoes. We use integral field spectroscopy from the Gemini
Multi-Object Spectrograph to analyse the 3D kinematics, ionization state,
temperature and density of ionized gas in the GB SDSS J224024.1-092748. We
model the emission line spectrum of each spaxel as a superposition of up to
three Gaussian components and analyse the physical properties of each component
individually. Two narrow components, tracing the velocity fields of the disc
and an ionized gas cloud, are superimposed over the majority of the galaxy.
Fast shocks produce hot ($T_e$ $\geq$ 20,000 K), dense ($n_e$ $\geq$ 100
cm$^{-3}$), turbulent ($\sigma$ $\geq$ 600 km s$^{-1}$), [O III]-bright regions
with enhanced [N II]/H$\alpha$ and [S II]/H$\alpha$ ratios. The most prominent
such spot is consistent with a radio jet shock-heating the interstellar medium.
However, the AGN is still responsible for $\geq$ 82 per cent of the galaxy's
total [O III] luminosity, strengthening the case for previous quasar activity.
The ionized gas cloud has a strong kinematic link to the central AGN and is
co-rotating with the main body of the galaxy, suggesting that it may be the
remnant of a quasar-driven outflow. Our analysis of J224024.1-092748 indicates
that GBs provide a unique fossil record of the transformation from the most
luminous quasars to weak AGN.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Davies_R/0/1/0/all/0/1">Rebecca L. Davies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schirmer_M/0/1/0/all/0/1">Mischa Schirmer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Turner_J/0/1/0/all/0/1">James E. H. Turner</a>Missing Gamma-Rays from kpc-scale AGN Jets: A Test of the IC/CMB Model. (arXiv:1502.07942v2 [astro-ph.HE] UPDATED)http://arxiv.org/abs/1502.07942
<p>The physical origin of the X-ray emission in powerful quasar jets has been a
long-standing mystery. Though these jets start out on the sub-pc scale as
highly relativistic flows, we do not have any direct measurement of their
speeds on the kpc scale, where the vast distances from the core necessitate in
situ particle acceleration. If the jets remain highly relativistic on kpc
scales, then the X-rays could be due to inverse-Compton upscattering of CMB
photons. However, the IC/CMB explanation predicts a high level of gamma-ray
emission, which should be detectible by the Fermi/LAT. We have searched for and
ruled out this emission at a high level of significance for the well-known
sources 3C 273 and PKS 0637-752, suggesting the X-rays are synchrotron, though
of unknown origin. These recent results with Fermi also suggest that the
kpc-scale jets in powerful quasars are significantly slower than have been
presumed under the IC/CMB model. I will discuss the surprising implications of
these findings for the energetics and radiative output of powerful quasars as
well as their impact on their environment.
</p>
<a href="http://arxiv.org/find/astro-ph/1/au:+Meyer_E/0/1/0/all/0/1">Eileen T. Meyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Georganopoulos_M/0/1/0/all/0/1">Markos Georganopoulos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sparks_W/0/1/0/all/0/1">William B. Sparks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Godfrey_L/0/1/0/all/0/1">Leith Godfrey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perlman_E/0/1/0/all/0/1">Eric Perlman</a>